Mirror Mark - Many thanks for taking the trouble but sadly, it's so different from the 420 that my skill level wouldn't be able to transpose it. Mind you, smart looking panel and easy to understand.
Marchi - OK, a little more complicated than the 420 (only 16 switches on that) but it's possible that I can pick out the bits I need so grateful thanks for your time. I'll let you know how I get on but in the meantime, if anyone can do an actual 420 - even if it's a copy of the one in your manual, it has to be better than mine! Utterly unreadable.
Cheers again, folks
Mark