Genius 235

[Unicorn5]

Preamble: Wordplay in 15 clues ignores one or a string of contiguous letters. In the filled grid these ignored letters produce eight words with a common theme.

I have the theme for this crossword, but am really struggling with the last four clues:
9A They discovered designer's initial in each tile (9) H???P???E
2D Surveyors fall behind in recession (6) ???L?P
4D African lands old soldiers around banks of Lake Chad (6) ???D?S
6D Style of note delivered from the south (4) ?F?O (I think this one is AFRO but I can't parse)

Any help appreciated. Thank you.

[Captain2]

4d Ve-LD-ts

[Unicorn5]

Thank you, Captain2 - I'd never have got that one!

[klazomaniac]

Tile is an archaic word for Hat/Headpiece. Struggling to make the parse though. Maybe yourself or Capt' can make sense of it.

[Unicorn5]

Thanks, klazomaniac. All I can make of it is an anagram of "each" around the outside with first letter of designer in the middle and then APIE are the letters that are ignored? But I can't find an APIE bridge! And can't make complete sense of it anyway.
HE-a-D-pie-CE
Can anyone parse/make sense of this now?

[scrunge999]

9a Headpiece

He = They ‘discovered’, plus D in ‘apiece’

[scrunge999]

6d is Afro I think, if this is one of the clues where some letters (here, ‘RO’) are ignored in the wordplay.

[scrunge999]

2d could be Gallup (the pollsters) - Lag backwards’ ignoring LUP in the wordplay.

[Unicorn5]

Many thanks, all.

[Unicorn5]

I have now finished the Guardian Genius 235 thanks to all your help. However, I have 17 clues (not 15 as per the preamble) where the clue ignores one or a string of contiguous letter. These are as follows: 11A, 12A, 17A, 19A, 20A, 24A, 26A, 28A, 29A, 2D, 6D, 13D, 15D, 16D, 18D, 24D and 27D. What am I missing? Thanks in advance.

[JJ109]

I hadn't realised that! I have the same 17 as you, and I am confident that the 17 answers are correct. I therefore believe it is a misprint in the preamble.

[Unicorn5]

Thank you so much, JJ109, your answer is much appreciated; I am now confident too!