The R4 frame used to sell for c£175 and was made from double-butted 7005. A 1997 advert says that with full XT and a Judy SL, it would have been £1,275 and quite a nice bike at a bargain price.
It would be interesting to know what it weighs, but on the basis of Total Bike's test of a smaller frame, I would guess c1.65kg for a size 19 (allow 100g for the headset cups and seat clamp). That would suggest a xc-level tubeset spec, rather than anything more heavy-duty.
The Total Bike test criticised it for having over-fast handling, but that's actually a good thing because they tested it with a P2 fork to get the price down, so the twitchy handling suggests that it needed a longer fork. Which is what you want to fit.
I don't know whether there was any link, but soon after that ignorant review, Ribble stopped offering mtb frames. I think they have continued to have a good reputation for road frames.
To be honest, you won't get much appreciation on Retrobike for riding a Ribble R4, but that's because people on here seem to think that bling-type decals are more important than what the frame actually is. They could tell you how much better their frame is than yours, if only they could catch you up.
