Mab wrote:
It's more the wind I am concerned about, rather than the cold. It's
already got significant wind burn.

I have my acer palmatum outside in a large terracotta pot here in N.
Wales (and prior to that in S.Bucks). It has survived the last three
winters.

My tree has presently got windburn, it didn't get quite enough water
this year.

I'm not worrying about it, the tree will shed its leaves soon, and grow
a new set in spring.

To keep your tree happy, wrap the pot in bubble wrap, raise it up
slightly to ensure good drainage. Put it in a wind sheltered spot if
possible - if not, perhaps try a windbreak on the windiest side for
extra protection. The trouble with attempting to protectthe whole tree
is perhaps causing moulds, and reducing the chances of rain watering.

HTH

Sarah