In reply to iusedtoclimb:
Lakeland 100 (again!)
Hardmoors 110
The Arc of Nutrition
UTSW (no longer running)
Spine Challenger
Fellsman (only 100k but cannot recommend this enough!)
Viking Way (ok it's 147 but who's counting!)
Offas Dyke 100
Cotswold 100
North Downs 100
South Downs 100
Autumn 100 (incredibly flat!)
UTMB (ok so this ones not even in this country!)
Happy to give you more details offline
These are the ones I've done to date