Awesome 531 is too flexy for me

In my experience big 531 frames bend lots under heavy loads, I sheared the seat tube off at the bb on my beloved Holdsworth whilst doing hill sprint reps.... but then I am 6'4" and 15 & 1/2 st..
FWIW I run a track frame which is much heavier than my old road frame, unknown tubing, although the forks are stamped 531 on the steerer. I run a 50 x 18 and even on long climbs it's super stealthy.
My Roberts (very highly recommended) has a hoooge downtube and flared seattube which helps nicely, even with 10 speed Campag there's no rubbing under power. If you're going custom these guys are great to deal with.

Roberts look fooking nice...........I don't think ive got quite that much cash for a new frame though!

I've just respaced and repacked my Campag hubs with new bearings.......going to be riding over to my girlfriends tonight so we'll see if that has made any difference!