Hey guys
Well I made at last some real progress!
The screen fault wasn't actually caused by firmware it was due to having the mains adapter plugged in, after doing some searching I found another user had reported his screen playing up when the mains charger is plugged in and as soon as I unplugged it normal operation resumed!
Prior to this discovery I also installed the latest official firmware, whilst there is a lot less functionality than the custom firmware it's easier to use so probably better for a novice user, the built in emulators seem to work well too and already have the buttons mapped which is nice.
I liked my Google account so all the software I've bought for my Android phone is available so that's cool, I already installed some games, etc and they seem to work fine.
So I'm reasonably happy now, my advice would be unless you know what you're doing buy one new as buying used although I got the unit half price has caused me a massive headache!
I'll do a full review once I've had the time to test everything out, I've just installed UAEforall so I'll let you know how that performs, it should be excellent ad it's fast and smooth on my HTC Desire HD.
ps. thanks Keropi for splitting the threads