The Case of the Missing Preamble by Ea

1. [Thematic answer (8, two words)]
2. Garden flat's value initially increased one hundredfold (4)
3. You haven't quite got the guts to appear on stage (5)
4. Alternative, lead-free (i.e. peeled) vegetable (5)
5. Newton is numb at first - e divides giant prime (8)
6. A couple of points were short, slightly sarcastic rejoinders (7)
7. French city turned inside out, but… (4)
8. …resistance in hiding in key Dutch network (4)
9. Balanced, structured articles about Y2M (11)
10. Enhance someone's A-level results? (3)
11. Blairism regularly provides material for Scottish comedians (4)
12. IVR located, aptly, in 18 (3)
13. Amounts to membership right within student body (7)
14. Served heart of swan with tail of newt - die horribly (6)
15. Mineral ignited during meteor break-up (9)
16. On beam, half-somersaulting was more easily manageable (5)
17. Dog sent up for Sweden in space agency rocket (5)
18. Range between E and F? (8)
19. Put German aristocrat in the dock, read out a collection of letters (8)
20. Where friar takes tray, perhaps… (6)
21. …take 250 assorted penniless old criminals (7)
22. Expand round waist - I can't see my **** without a *y*mt** (sadly) (9)
23. Voyager - very basic RE? (6)
24. Something of old priest taken to heart by Roman Catholic? (5)
25. Goat-antelope - half goat, one-sixth reebok and one-third impala (5)
26. Engineers new clone of French fragrance (9)
27. Over a hundred body parts (4)
28. Bishop wearing curly endive that's caught hovering around parks (7)
29. A hand in what pietà represents (6)
30. [Thematic answer (8)]

To enter this competition send a full solution (as a word document or in Henry Casson's cxml code) showing the bars to Solvers should also submit a clue to the word which appears across the middle row of the completed grid. The writer of the winning clue will receive a copy of Edream's Reference Suite, including the entire Encyclopaedia Britannica, World Atlas, English Dictionary, Roget's Thesaurus, Quotations & more... This prize was donated by Edream.