In reply to Tigger:
Did you ever get onto this?
I did Big Thing Coming yesterday. Great route and the pegs looked as trustworthy as old-ish pegs ever look. Which is to say, who really knows! They can be backed up with wires or small cams, though that's pretty strenuous, especially if you're stupid enough to get on it in full blazing sunshine like I did yesterday!
If you're using the new Peak Limestone South, be wary because I think the line is wrong on the topo. The line seemed obvious enough once I was on it but there's definitely a mismatch between the description and the topo. I'd go with the description because the topo line is completely blank at the top.
I think that the line for the next route left, Frank Carsington, is probably offset at the top as well but I don't know for certain having not climbed it.