Thanks people, found another mouse, which was presumably an A500 one coz it didn't say 1351 on the bottom and worked. Must have 'em stashed all round the house, didn't find the motherlode of miggy stuff yet, but had an A500, found a stray PSU and a few disks.
That A500 appears to work, loads Octamed off disk, but haven't got anything on other disks out right now, couldn't do much with it. Plugged in the promigos HDD and it's glitchy, got a sofware error once trying to boot it, nothing much else happens, though I can see it in Octamed's file requester as D0H0: which it says is not a DOS disk.
Anyhoo, appear to have one working Amiga... now to find the others and some software...
RW222