Thanks Frode :) To all who have downloaded, I suggest adding the line:
90 POKE 28978,53 to the AUTO file and re-saving it!! Much more like it :) It gets a bit cramped at the top because, I've just noticed, I'm starting the blocks far too low down! I also wish I'd fixing the flickering earlier on but never mind. I'm quite pleased with how this is going now, but I am sorry I announced it being almost completed when I did. I literally thought it would take a couple of days to finish it when in reality I had barely started.. Oh well, you live and learn :) Rob.