Pruning a rosa warm welcome 'Chewizz' when moving to a pot.

Good morning all gardeners!

I would really appreciate any advice on my 'chewizz' climbing rose.  It has been in the ground for a few years but I am trying to reposition it as redesigning the garden.  So I am trying my luck at growing it in a large container.  Hopefully you don't think that is sheer madness. It has grown to about 2 metres high. I would love to hear from you experts ou there how much I should cut it back to give it it's greatest chance.

Huge thanks in advance for any advice! All the best x