Great puzzle as usual from Virgilius but if there’s something going on here connected with 1/29 then it’s passed me by completely.

Common abbreviations used
dd = double definition
cd = cryptic definition
rev = reversed or reversal
ins = insertion
cha = charade
* = anagram

A delightful puzzle both entertaining and challenging

Across
1 TABEFY *(be fat) Y (you start) to tabefy is to waste away
4 AMPUTATE Ins of PUT (place) in A mate (a partner)
9 AMOURS 3 is forenoon or AM (ante meridiem) OURS (pertaining to the Guardian, the paper where this puzzle appears)
10 INSCRIBE simple charade
11 BLENHEIM ORANGE Cha of Blenheim (battle) Orange (an IT brand) The irony of an apple being called an orange !!!
13 PIGEON POST After the 1936 book by Arthur Ransome (1884-1967)
14 ADOS rev of soda, something splashed to a hard drink in a watering hole
16 RAPT homophone for wrapped
18 BRAIN WAVES John Wayne and the Indian braves … Spooner clues always make me laugh
21 ILL-GOTTEN GAINS Clever cd unlike the biblical death
23 LADISLAW Simple cha after one of George Eliot’s characters.
A noteworthy case of a lady author having to assume a male pseudonym
24 DILATE *(detail)
25 SUNDRIES So that the sun can dry the wet clothes
26 AGGERS An agger (new word to me) is defined as mound but how the commentary box relates, I do not know

Down
1 TOAD To advertisement (display)
2 BOOTLEG This is the third time in the last week or so when I have come across this Merseyside town of Bootle; used variously as part of bootless and now bootleg. Force is, of course, the gravitational force represented in physics as simply ‘g’
3 FORENOON Foreign minus GI (soldier turned out) + 0 (nothing) ON
5 MANUMISSION Ins of UMIS *(musi-c) in MANSION. Formal release from slavery
6 ULCERS *(clues r) What lengths compilers will go to to entertain us
7 ALIGNED *(dealing)
8 ELEVENSES What a delightfully quaint word we seldom hear nowadays. In my younger days in colonial Malaya, the morning tea was thus called and lunch was tiffin. I understand these two terms were also popular in India during those times
12 EXPORT TRADE Homophone for X (unknown) Portrayed (depicted)
13 PARTICLES Part (some) *(slice)
15 SWEARING Ins of EAR (listener) in SWING (yesteryear’s pop)
17 PALADIN simple cha
19 VINTAGE *(given at)
20 MOUSER MO (medical officer or doctor) user. Definition very cleverly disguised as Tom or a cat
22 HERS Herpes (disease) minus pe (exercise)

From FT Monday 16 June 2008
Common abbreviations used
dd = double definition
cd = cryptic definition
rev = reversed or reversal
ins = insertion
cha = charade
* = anagram

Across
1 GELIGNITE Cha of GE (one third of German) LIGNITE (coal)
6 MOPED dd a light motor cycle
9 REENACT *(a recent)
10 GENERIC Cha of GEN (information) and Eric
11 HOARD Ins of O in hard (cold)
12 RESERVIST Ins of E (English) RV (Revised Version or Bible) in RESIST (fight)
14 SAD Rev of Da’s (fathers)
15 OPERATIONAL Ins of E (earl) RATION (helping) in OPAL (stone)
17 BELLRINGERS they do create peals, don’t they?
19 CAN can (e)
20 CONFORMER Cha of CON (mislead) FORMER (one time)
22 ANVIL ha, a bone in the ear
24 INERTIA I + *(retain)
26 VILLAIN Ins of ILL in VAIN
27 ENSUE EN (Rev of NE, Nebraska) SUE (appeal)
28 TIREDNESS TI (rev of It, Italian) Redness (blush)

Down
1 GIRTH *(right)
2 LEEWARD Cha of Robert E LEE & WARD (a charge or pupil)
3 GRAND TOUR Ins of RAND (SA money) in GT (gran turismo) + OUR
4 INTERREGNUM *(run regiment)
5 EGG ha
6 MANOR Cha of MAN (occupy the store?) OR (gold) ; seat of a nobleman in feudal times
7 PORTION Ins of R in POTION (tonic)
8 DECATHLON Ins of ECATHL *(chatel) in DON (university fellow)
13 SLAVE DRIVER Ins of DRIVE (trip) in SLAVER (Chambers : drool vi to slaver; to drivel; to show effusive or lascivious pleasure)
14 SUBSCRIBE subs- crib- e
16 INSTALLED inst - all - ed
18 LANCERS dd lancer n a light cavalry soldier armed with a lance, or a soldier of a regiment formerly so armed. lancers n sing a set of quadrilles, first popular in England about 1820, or its music.
19 CAVIARE Ins of VIA (Roman way) in CARE (be concerned)
I wonder whether the strict rules of Ximenes have been transgressed upon. “Be concerned” would be “cared” and not “care” But I am not a native so I shall wait for some natives to put me right
21 OUTRE *(route)
23 LINES dd I wonder whether they still punish students by giving them lines … in my schooldays, I did do a lot of writing :-)
25 ACT Cha of A (American, see A3 in Chambers) CT (court) In UK and other Commonwealth countries, an Act of Parliament, when passed, becomes the law of the land.

Two surprises. The puzzle was uploaded much earlier than usual. The setter appears to be new, for I have not encountered the person before. The setter’s psudonym does not figure in the list somewhere on this site.

I have solved most of the puzzle but I must admit that the two 15-letter acrosses are still eluding me.  Both seem to be anagrams. I am resisting the use of scribble pad.

In the first foray, I got 9, 12, 25, 13, 17, 24 in the Across set. For further progress I had to switch to the Down set where I solved  2, 4, 13, 22, 18, 15, 20, 1 (both in that order). A couple of others were obtained later.

Let me see if I am able to get past the roadblocks.     

* * *

PS1: I have since solved the two long anagrams - not with any anagram solver, electronic or paper, but by resort to paper and pen, writing down knowns and unknowns and marking the word divisions. Well we may expect these from a “courtier”. Solving the top one helped in getting to the finish in the lower one.

* * *

PS2: And it turns out that most of the clues that I did not get in the early stages are those relating to the theme of the puzzle. I got all except two which I am not able to recall. 

Across

7 CENTRE COURT ROOF - anagram of ‘for concert route’
10 DEDUCE - container/contained - de(d)uce
16 LENDL - ref. to the defeat of Lendl by Cash - ‘racketeer’ is a facetious term for tennis player
19 BLUE PETER - charade - blue (sad), Peter (disciple [of Jesus]) - solved from wordplay - ‘Blue Peter’ is a blue flag with a white recangle in it; it is hoisted when a ship is about to sail
21 Not solved - (On edit: For solution, see comment below)
24 IGUANA  - charade - I, g, u (being the first letters of ‘go up’), Ana [Ivanovich, Russian tennis player] (On edit: Serbian)
25 REINDEER - hom. of ‘rain dear’ - Not too elegant a surface reading.
26 FOUR MATCH POINTS - anag. of ‘important of such’

Down

1 RETRIEVE - c/c - re(tri[-p])eve
2 STUDIO -charade w/ anag. - stud (anag. of ‘dust’)I,o 
3 HELOT - charade - he, lot
4 CONFIDENCE TRICK - cryptic def.
5 BRADFIELD - anag. of ‘bid Alfred’ - it is a tennis academy
6 ROSCOE - c/c - ros(Co)e (On edit: Answer revised in the light of a comment below.)
8 RODDICK - c/c - r(odd)ick - U.S. tennis player Andy Roddick
13 ALDEBARAN - anag. of ‘Lana bared’ - It is “the brightest star in the constellation Taurus and one of the brightest stars in the nighttime sky”. I had to look up! I have to look up!
15 OPEN AIR - charade, open,air (v.)
18 TOILETTE - c/c - to(I let)te
20 LEGION - charade - leg,I,on
22 ORDAIN - charade - or,dain (hom. of Dane)
23 Not solved -  (On edit: For solution, see comment below)