In reply to 1176gws:
I've never climbed in Northumberland, but I've heard that there are VSs up there that will shut down an average E4 leader.
I've climbed quite a lot in North Yorkshire. On the trad limestone, e.g. Malham Right Wing I found that HVS 5b was usually steep, sustained and fairly well protected 5b (and hard because of polish) - and thus would be graded E2 in Pembroke.
On the grit the grades often seemed hard too. A lot of people get a hard time at Almscliff but I don't think it's too bad, more a style thing: the routes are very strenuous.
Basically Yorkshire and Northumberland have massively stiff grades, completely different to other areas. I haven't climbed in Orkney, but I have climbed in NW Scotland where I irritate several people on here by banging on and on about how the grades there are really soft. Like E3s that feel HVS type soft. Maybe Orkney is nearer that end of the scale, I don't know?
The massive regional variation just makes a complete mockery of the idea that the grades offer an objective scale of difficulty. They're not, they're just people's opinions, biased in all sorts of ways in different places.