In reply to Jon Stewart: Apologies for any repetition but:
Mask of Red Death - Superb, especially upper section, should definitely be done in one pitch. Low in the grade but 'out there' at the top though good kit nearby.
Centrefold - Again superb, I thought this was a notch harder than Mask of Red Death though there was a crashing sea beneath me after we abbed in so I guess that adds to things. Does need a bit of commitment pulling through the bulge though. Reasonably sustained and bit steeper than it looks. Good gear throughout.
FWIW I thought The Sun was E3 too and not the easiest either as some would suggest.
An 'easy' E3 I have done at Gogarth is Kalahari, really good, steady, open climbing. Just feels a bit tricky after you step right into the short groove. Difficulties are short lived.
Holyhead has some good E3s: Sai Dancing is brilliant and at the harder end of E3, but very well-protected (slight sense of urgency / don't fall off at the start however). I thought it might be 6b going right at the top and the final pod is awkward. Really worthwhile.
Just left of that is The Final Solution (previously known as Penny which is now the name for Katana) at E3 5c. Really good and shares a chunk of climbing with Sai Dancing. Again, very good gear and this saves hardest to last, bit of oomph needed to exit the crack. Low in the grade though does have quite a big feel.
Nearby is Big Jim: physical and short-lived but with a sense of urgency, good gear with slightly bouldery climbing for the crux. Safe to fall off. Hard.
Strike on the Upper Tier is exceptional, really suits my preferences. Has been E4 but should feel 'easy' if you're fit and can hang around to get gear in (bombproof large runners). If not E4 then at the harder end of E3.
I haven't done much else (anything!) at E3 on Gogarth - must do better next year! I have seconded Wonder Wall at Easter Island Gully, this felt hard and with a very on / off crux, though it wasn't great conditions and I often get tangled up when seconding.
Good luck with the quest, hope to see you on Rat Race...