As of February 2002, Rainbow were still operating - I rented an R22 from there over three weeks, but no f/w stuff.
Facilities wise, the place was a dump, but I think they've moved. As long as they've got shot of that spongy sofa when they moved, you should be OK.
The R22s I flew were well maintained, if a little worn. I did have a minor problem where my request for booking an a/c all through one week had been missed, but the owner rectified that in 5 minutes with a pencil and rubber.
Try ringing them - they should be open at about 4pm UK time.