A typical Araucaria crossword, which hinges on being able to solve one key clue.  In this case the key answer was the one at 19ac.  Once you have that worked out, the rest (almost) falls into place.

Of course, being an Araucaria puzzle, there is the usual mix of obscure words and phrases, and some “challenging” wordplay, but, all in all, an enjoyable puzzle that leaves you 19ac,8 when you’ve finished it.
ACROSS

10,25 TEMPE-RATE - Tempe being a valley near Mount Olympus, noted for its rugged scenery.

12 CAT-A-MOUNT - another name for the puma

14 SAT-ANIC - (homophone of ALNWICK, a castle in Northumbria)

17 CAPRI(corn)

19,13 CON-SCIENCE - this gives you CON for 19ac, and these three letters make up parts of answers and clues throughout the puzzle.

21,19,1 ALLEGRO CON MOTO - (organ cello)*-MOTO - a musical instruction, meaning “quickly and lively” (is “livelily” a word)

22 SEGRAVE (homophone of SEA-GRAVE) - very clever clue, as Sir Henry Segrave died on Lake Windermere while trying to break the water speed record in 1930.

24 WATERFALL - not sure about “force in the North”?

26 TIT-US - as in “Titus Groan”, the hero of the Gormenghast trilogy by Mervyn Peake - sitting on my bookshelf waiting to be read.

29 EVACUATED - (due caveat)*

DOWN

2,19,16 CHILL-ICON-C-ARNE - Thomas Arne, composer of Rule Britannia

3 (cen)TRE-PANNING - removing part of a bone, especially the skull

4 CIRC(L)E

5 JETTISON - JET (1’s not)*

7 I’M-PUG-NED

13 S-AC(c)RA - wedge-shaped bone in the lower spine, made up of five vertebra

15 THOUGH-TFUL(<=LUFT) - the definition is CON-SIDE-RATE, words appearing in the crossword.  LUFT is the German for “air” as in Luftwaffe and Lufthansa

18 PI-LOT-AGE

19 C(hurch)-HOT-APE-G - apparently a “chota peg” is a small drink

22 (con)SULTAN(t)

24 WELL CONTENT - a reference to “Alice in Wonderland”, I presume?

Has anyone else notice that the FT bloggers are always first to post, bright and early and reliable as a Swiss train, followed by the Indyites, while the Guardianistas (myself included) roll up haphazardly at any time of day?

Across
1. BACKFIRE - BACK + FIRE
5. ARCTIC - C in ARTIC (artic being an abbreviation of articulated lorry)
9. PECTORAL - anagram of CLEOPATR. One of the breast anagram indicators I’ve come across in a while!
10. ASCENT - AS + CENT
12. SHOW TRIAL - anagram of IS WORTH A + L
13. WHOLE - homophone
14. GRIT - R in GIT
16. POTTAGE - OTT (for Over The Top) in PAGE. I guessed this from the common French word “potage” and verified the English word in my dictionary.
19. ROUNDER - double definition. Rounders is an English children’s game with a slight similarity to baseball; I assumed that “rounder” can mean a run in this game although I don’t recall ever hearing the word used like that.
21. PARR - double definition (Catherine Parr was Henry VIII’s last wife)
24. ADIEU - A[ustralian] + DIE + [yo]U
25. SCALLYWAG - ALLY in SWAG
27. ICICLE - hidden word &lit
28. TIA MARIA - A in TIM + ARIA
29. MINUTE - double definition
30. REDOLENT - DOLE in RENT

Down
1. BYPASS - BY + PASS
2. COCOON - CO + CO + ON
3. FLOAT - O in FLAT (as in milk float, an electric vehicle for delivering dairy products)
5. REALIST - RE + A + LIST
6. ROSE WATER - AWE (reversed) in ROSTER
7. TEETOTAL - TEE (meaning supporter as in golf) + TOTAL
8. CATHETER - THE in CATER
11. FLIP - double definition
15. RED MULLET - RED + MULLET
17. ORGANISM - anagram of IS AMONG around R[iver]
18. AUDITION - AUDI + I in TON. “Hundred” as a clue for TON is a good one to keep in mind; it can also, of course, clue C.
20. RASH - double definition
21. PRALINE - anagram of PLAINER. A praline is a type of sweet made with pecans and associated, I believe, with New Orleans.
22. SWERVE - W in SERVE
23. AGHAST - hidden word (well hidden)
26. LIMBO - B in LIMO (Lincoln being a marque of limousines)