Thanks Frank,
I think I should have asked you guys for input first.
I was working on the basis that the manual hand cranked one I purchased from some great guys in Poland works really well, granted on 30 mm tube.
The cylinder is on the centre line and the rollers have been machined to 1/2 of the materials diameter (scaff pole). I didn't think about the 4 x OD for the rollers but it makes a lot of sense. I was thinking of wimping out when applying the force onto the pipe, I tend not to go for broke with tools anyways.
I very much appreciate your offer of luck, I think i will need it.