In reply to amadan:
You'll toil for many crags with a good selection of Diff/V.diffs in one location - most likely you'll need to jump between venues doing a route or two at each. A lot of the diffs tend to be pretty grotty as well or descet routes so be wary!
Try Souterhead - a reasonable number there.
Black Rock Gulch has some good severes if you feel up to trying severe.
Theres a few diff / vdiff / severes at Pass of Ballater as well if you're further a-field. Though Ballater is best at VS+ imo.
Cheers.