Spotted...

6ft, but 35 inch legs and monkey arms.
next frame will defo be aroun 58-59 rather than 56-57. My road bianchi is 57, and I now know I should have got the 59, but you live and learn.

@Ed, yes comfort mainly - nicer on london roads, feel a bit more stable in the wet too, plus being on the heavy side I'd rather have more rubber under me (ooer!)

if I were you, go to a bike shop like Condor where they have a tailor bike where they can adjust it to fit your need, and be able to find out exactly what measurment you need.