Any hints and suggestions on how to proceed beyond working out that 8 down (the only answer with 13 letters) must therefore begin with c (and could be "comprehensive"). Obviously it would help if I could solve a few more of the clues, but with 20 odd still to go, i can't ask for so many solutions !
I would however be glad to know "The weakest of a litter (7) = D??????"; only word iI know for this is runt.
Thanks again MLN; I've finished it now; I had not initially realised the across clues were in alphabetic order. Whether I will ever come across some of the words again is highly doubtful ! !