I finally got my mandrell bends in 1.75inch tubing, which turned out to be a fair headache.
Apart from finding two places that said they could do the centre line radiussseess that I wanted, I went on to order tubing for the benders to do the job, then having one lot done, the other supplier then rang me and said they couldn't do the matching radius.
Long story short, the second guy must have felt guilty about wasting my time and money so he found me some....acruss the dutch..........in New Zealand.
I am happy with the end result............but my head hurts.