I am not aware of a cloche that size, how would you anchor to the terrace so it stayed in place in winter?

what about bubble rap ?

What plant is it exactly?

I would not use bubble wrap as that will cause rot. Fleecing it during cold spells/winds works for semi-hardy plants. Anything needing above 5C is going to die regardless of shelter.

I have a large cordyline growing in a pot that I like to protect in winter.
I create a wigwam type structure of canes inserted into the pot then wrap the whole thing in garden fleece. You will also need to protect the roots by insulating the container as well. The trouble is that it doesn't look very attractive for 4 months of the year.
I would also suspect that it would depend on what plant you are trying to protect and whereabouts in the UK you are. I don't think I'd attempt to bring a houseplant through winter outdoors up here in Scotland.

I did a blog a couple of years back, you can see it here with pictures of how I did it, hope it helps you a wee bit.

http://www.growsonyou.com/scottish/blog/21853-wrapping-up-for-winter

That is good winter protection Scottish. I would only do that if bad weather is forecast (dare I mention winter 2010). I am hoping for a repeat of last years almost frost free winter though a lot drier.

Thanks Botanic. I think we'd all love a repeat of last winter. We can but hope :)

20Q what plant are you trying to protect?