Thanks for those - the answer now gives me QUD for 22a which was ... which was proved to be a bit inadequate in retrospect (3) - Is this a word? I had Trafalgar Square in place to give me the 'Q' - have I got this all wrong?
Thank you Sandy Roe and Quiz Monkey for that help - although I have finished the crossword now I am not sure I can tie up some of the answers to the clues! I will have to investigate further! I am still getting used to these crosswords!!!