In reply to cb294:
Yes, I suppose the main thing you need for an old relic surviving is a)climbing to have been taking place then and b) really heavy-duty bits of gear. Apparently the 'bolts' on Czech Sandstone(and German) had to be large enough for you to put your shoulder through, so that you could untie, feed the rope through, and then retie. That means they're pretty big and can survive pretty well. Climbing has also being going on for yonks too.
If you're talking about UK gear that was placed for the intention of recreational climbing, then I guess you'd have to go to the lakes?