Nige wrote:

I need to bend some 22mm copper pipe into quite a wide radius curve -
is it possible to use conventional pipe benders to do this (the type
with long handles)?

It's just that from looking at them, they appear to have a fixed radius
former - or is there a way of increasing the radius of the curve you
make?

Above all, I need to produce smooth curves - is there a better way of
doing it?

Any advice would be appreciated...

For very wide radius, you can use your knee, and just pull on the pipe
till it just yields, then move along a bit.
For anything other than very shallow bends (say a meter radius), this
method won't really work.