I was pretty much a Beeb man originally but decided to try a A3000 off the usual auction site
Pretty pleased with it in that the dreaded battery wasnt in too bad shape. I have replaced that with the CR2032 style one off the Amiga site that someone had recommended. This is a nice little package and avoids regularly desoldering to replace. All good so far
It has the original OS (3.0?) and boots to a screen like this

I dont have a mouse yet and looking to get an adapter
I've bought what should be OS 3.11 ROMS. I fitted them, moved LK20
I only get the blue / red screen flashing and nothing else
Tried Delete power on, no joy
Put the old ROMs back and and it boots back to the previous screen (In case it helps I havent yet plugged the floppy back in)
I did a quick bus of the CMOS chip and OV and 5V seem good
Grateful for any thoughts