So are holiday cottages etc allowed to open?

[Sandyplankton]

It isn't clear to me at all whether that's allowed or not.

Yes but depends on your tier on whether you can stay in them

Thats not what the government website says

It says "You can stay in a hotel during the Christmas period, including in a tier 3: Very High alert area but only by yourself, or with other members of your household.

You can stay in private rented accommodation with members of your household, or your Christmas bubble"

They are all allowed to operate irrespective of tier between the 23-27th December, outside of that period then only if in Tier 1 or Tier 2. Really hoping North East scrapes into tier 2 as would love a pre Christmas break !