When I saw the special instructions, I nearly decided not to bother, but I'm glad I did, as it was fun and not as difficult as it looked like it was going to be.
Two I can't fully parse, though - any suggestions?
(There is an extra letter not given in the wordplay in each answ
1d School subject's stopped because it's of little value (8)
No idea, except my answer is of "little value"
20d South African sailor kidnapped by Chinese people (6)
Why "South African"? It seems totally superfluous.