knotweed?

That looks like the closest match so far, Thank you for all your help. I reckon mine is also rooted somewhere inaccessible. So I'll just have to keep cutting it back every few weeks in the summer months.

 

It certainly looks like a vine of some kind. Actinidia sounds like a possibility. If you really want to get rid of it I think regular treatment with glyfosate painted onto the leaves where ever you find them is the only answer. It needs to be grown under glass in this country to get it to flower and fruit. There is a lovely variegated one, Actinidia Kolmikta, which has green leaves splashed with white and pink.
The treatment for knotweed is injecting weedkiller into the hollow stems. It is a notifiable noxious weed now and councils will treat it for you, probably at a cost. Japanese Knotweed does not climb.

 

"Crimson glory vine" = Vitis coignetiae see Vitis coignetiae | crimson glory vine Climber Wall Shrub/RHS for more info.
Treat with a glyphosate containing weedkiller if you really want or need rid of.

 

Apologies; but to me that sounds the worst form of variegation possible.

 

I think Actinidia is a twiner, I thought I could see tendrils in one of the pictures.

 

Kiwi often need a pollination partner but there are a few self fertile varieties. My initial thought was it's a kiwi but it looks woody at the base. I think crimson glory vine is probably correct because of those grape like tendrils.

 

Each to his won.