am almost there - can't see the anagram for 2: pie and frog give me nothing. It's obviously about mushrooms but if the Latin species name is the first word, I can't see the second.
Excellent crossword, Hamish, though some very obscure words ... I pride myself as being something of a Shakespearean myself (having directed most of his work) but my Shakespeare's Words by the Crystals tells me 8 is only used once at the very end of what's likely to be the last play which was only partly written by him - so "Stratford" is a bit steep, I feel. The Globe burnt down at about the time the word was being uttered!
Was held up on 20 by alternative spellings ... bloody Dutch!