Yep, just got a nice new pipe bender and gave it a trial.
The first bit of 20mm steel pipe went well and no probs.
But the 40mm gal pipe i stuck in there.

So I'm looking for suggestions on how to release it.

The obvious one is to hit the cast iron fitting to free it, but I'm
wondering if there is a better way.

And did I do something wrong and if so, what should I have done?

TIA (thanks in anticipation)