Even though the “theme” is pretty obvious, on immediate inspection of the clues, the category itself (boys’ names) is pretty expansive.  So it still took me a few minutes to figure out the last couple of four-letter ones.

Across
1 ROB(ER)T
4 BRAD,SHAW - the eponymous post-war “Bible” of railway schedules. I think its disappearance more or less coincided with the rise to notoriety of the “British Rail sandwich”, sometime in the 60s/70s.
9 G(ERA)LD - the “Good Lord” container had me initially putting in Geramy. But it was tentative and soon corrected, fortunately.
12 NU,MIN(O)US - “new” + love in minus
15 LIAM (mail) rev
20 TI,MOTHY - I couldn’t help but enjoy the neologism mothy for “insect-like”.
21 JOHN - ref J. Bull
26 (-p)ENTANGLE
30 S,TRIDENT - I still can’t make up my mind whether or not I approve of these stuttering clues (”s-submarine weapon”).  Everything in moderation I suppose….
31 AL(B)ERT

Down
1 RE(GIN)AL,D(-ig)
2 BE,RIMBAU(-d) - this “Brazilian instrument” was unknown to me but, having spotted Rimbaud early doors, it was a pretty confident guess.
3 ROLAND - ref the old knock-knock joke…Who’s there?….Roland Butter.
5 (-a)RYAN - the last one to go in for me.
7 HU(BER)T - The most obscure of our three Berts today. “Last month’s end” = (Novem)BER.  In his youth, Smiffy lived in the only parish in the UK named after St Hubert.
17 BILL,FOLD - a tricksy one, as (uniquely for this puzzle) the “boy” here is only part of the wordplay, rather than the entire answer.
18 LON,GACRE - (grace)*. An &-lit, supposedly. Although I don’t recall it being synonymous with “grace”.
24 SA(MU)EL - Mu in leas(rev)
27 SEAN - hidden. But took me an inordinate amount of time to spot, because I became mildly obsessed with the (superfluous) word “discipline” in the clue.
 

A pleasing puzzle by Dac.    Solving time: 18 mins

* = (anagram)*   < = reversed

ACROSS

1 DEF (l = L) ECT       Excellent misleading surface

11 RO (A) ST (i)      Rosti is a Swiss potato dish - the type you eat, rather than one you put things in

12 COLLECTED     Another very good surface - double definition

17 CHANNEL FOUR      (RAF luncheon)*     Auntie = BBC   Not its only rival, of course.

20 EXEC (utive) RATES

22 NOYES      Hidden reversal indicated by ‘retired’     A poet, once a basis of a Listener crossword, if I recall, playing around with no and yes.

23 MASS AGED

25 Y O (SEMIT) E    Times<

26 ME(R) LOT    (motel)*     R = waiter’s last

DOWN

2   FIL (MAB) LE(t)

3 CAT A TONIC

6 I (one)  M (mark = German currency before the euro) (p) AGE

8 PARADE      Defined by the final word in the clue ‘display’, I think.     I did not research further to see if it also fits the wording of the rest of the clue but it sounds a likely title for such

12 COM (PARTy) MENT

19 V (ERSE) S     For once Irish is not ‘Ir’ but an older name for the Irish language

21 REAR M     A very pleasing &lit to complete a very enjoyable puzzle.

A pretty tough one this, took a good half hour and left me in doubt about the wordplay of two clues, including the main theme-word. But I think I’m there now. I thought at first that there was a historical theme, then was surprised to discover it was football. In the end, of course, it’s classic Araucaria, linking diverse themes through Chelsea/Stamford Bridge.

ACROSS:

1. HAR (RAH<) OLD. Got this after I saw the historical theme.

2. LONGWAYS. Not quite sure about this - going the long way may involve a lot of turnings, in my experience.

9. SIN EW Y. I think the definition - ‘using muscle’ is justified in a poetic, if not a biological sense. I couldn’t get the wordplay for agges, but it’s wrong = SIN, (bridge) partners = E and W, yard = Y.

10. MO(UR) IN HO. Former Chelsea manager, not now to be England’s.

17. (Win)CHELSEA. Not sure where Winchelsea is (Kent?), but I guess it’s no longer a port. I guessed this from C_E_S__, and then saw 10ac, but it took a while to work out why.   

18. PRIESTCRAFT. A difficult anagram incorporating two abbreviations (FR RC APTEST I).  I think this kind of thing’s generally regarded as OK if the abbreviation is obvious, making the anagram direct and not indirect. This applies to RC, but not FR, which could be PA, DA. Of course, it didn’t help that the paper version had the word length as (10).

22. HAUNTING. Double def.

23. SENLAC (LANCES*). Scene of the Battle of Hastings (4dn), which followed that of..

24. STAMFORD BRIDGE. The theme-linker - Chelsea’s ground, and scene of 1066 victory for Harold that preceded his defeat at Hastings.

DOWN:

1. FLOWER SHOW (SHOWER FLOW). Another Chelsea event.

3. A G-GRIEVE.

4. HAS TIN GS. Tin is old slang for money, so I suppose ‘HAS TIN’ means ‘can afford’, although pedantically speaking, what you can afford depends on how much tin you have.

7. AUNT. Is an anagram ‘of’ 21, and a part ‘of’ 22. 

12. P(ENS)IONE(e)RS. Yet another Chelsea link. All that’s missing is a reference to Elvis Costello’s “I don’t want to go to Chelsea’.

16. TIP STAFF. I’m sure it’s been done before, but it’s neat.

19. C(HER)RY. Nice definition - ‘with heart of stone’?

20. THUS. I’m not sure who the poetical goddess is, but added to THUS, I’m sure she’ll make a flower - ACANTHUS, AGAPANTHUS or some such.

21. TUNA (A NUT<).