I'd try to untangle and lay on the ground whilst you erect the new arch then tie back into.

Good advice MG. I did the same thing with a passion fruit vine growing in a pot that I wanted to move from a trellis to grow around an arbour with seats that I built ... Carefully untangled it and laid it out in the garden and dragged it over to the new position.

What I found was that it's very easy to damage the shoots by creasing them or breaking them off completely. Take your time, be gentle with it and it will be ok.

and if the worst happens they will regrow from the broken stems and from dormant buds.

I would try to untangle it. When my fence had to be replaced two years ago, I cut my beautiful variegated summer Jasmine hard back. I really regret that now as it is only just coming back. I would use it as an opportunity to tidy it, but don't be too drastic. You can always prune again if you have not done enough.

Thank you everyone, I thought that would be the best option. Would it be best to do it now before new growth?
Just worried if I break any 7 then have a frost.
Many Thanks

do it while its dormant then any stems that do snap off will then trigger dormant buds lower down in the warmer weather. also less new stuff to get in the way.