In reply to Bottom Clinger:
I have my copy of the AA Readers Digest Book of British Birds (1st published in 1969 - some of the info may be out of date but the main illustrations are still stunning). Pages 374-377 have some lovely illustrations of various chicks & ducklings. I'd always wondered how accurate these were, they only confirmed the Eider (already knew that one) but gave me the Gadwall - I guessed they weren't "merely" Mallards since that was also a possibility.
I must have been very close to some Red Grouse chicks in the Lakes the other day judging by both parent birds doing the fluttering "oh look at me I'm struggling to get away" thing - but no sign of them - they know how to stay still & quiet.
Some wader chicks next please to further test the book (or game birds, or gulls, or terns).
Post edited at 22:44