In reply to pepperpot:
One of the peak guides (possibly Dark Peak by VG) has a "Lord of Loops", though I've not done it (yet). Something like 60 miles. Further north (Hebden Bridge) is the Mary Townley loops, which looks quite interesting.
And even though you say you're not into events, I can recommend the Kielder 100 if want a really big challenge - what appealled to me (apart from the distance) was the fact it was a single loop, so relatively few traffic issues