As I expect you know, Jasmine polyanthum isn't entirely hardy. Fortunately, living in central London gives it the best chance of survival in this country, unless its in a very open and exposed position facing north or east.
Try bubble wrapping the pot and placing horticultural fleece over the top growth, anchoring it down in some way, if we have severe weather this year.

Thanks very much for that advice - should I take it indoors? What is horticultural fleece? I live in the NW but think the patio faces West.
Thanks once again
Argentaangel

Horticultural fleece is a soft, fleece like covering, available on line or from garden centres, specifically for plant protection. Comes in various thicknesses.
I forgot to deal with your query re watering - check the pots occasionally during winter, but usually, watering is not necessary from November through to early February - if February is warm, bright and sunny, you may need to water then, if not, March. Unless your pots are entirely out of the rain, when you'd need to check more often.
If you want to move your jasmine indoors if we have some really bad weather, you can, but only if you have an unheated but frost free room available - moving it in and out of heat isn't a good idea.

Once again thank you for your advice which is very helpful
Argentaangel.