Right, thinking towards 3 Peaks time again and prepping my cross bike got me to thinking that actually, maybe the frame’s a bit big – it looks and feels like a gate… I remember reading somwhere about CX bike frame sizing in comparison to road bike sizing and that you should go for a smaller frame on the CX bike because of the differences in geometry, BB height, type of riding, et, etc, but can’t remember what the advice is.

All I want to do is swap all the componentry on the current CX bike over to a new frame (looking at getting something from Paul Milnes in Bradford for a decent price), so, what’s the general STW advice for a suitable frame size for a roughly 6 foot, 32 inch inside leg male?

56. I ride a large in Specialized MTBs, and a 17.5″ Genesis, and the 56cm CX fits me fine.

Generally the advice is to go down a size compared to a road bike for racing.
This gives you a more upright position, increased stand over and makes it a bit easier re mounting and dismounting.
After that it depends whether your road bike is slightly big or small, whether you are buying from the same manufacturer etc etc
Would have thought you were in the 54-56 range

Same size as your road bike, just run a 1cm or so shorter stem and maybe a bit higher. Smaller frame won’t result in the saddle being any lower so it’ll make no difference to remounts.

I am 5’11” and 32″ leg and 56cm always fits me.