Yes, it is just 4 nights for self catering - this is from PASC (industry body):
⁉️Common Christmas Bubble England questions⁉️
More questions about the Xmas bubble than anything else, so here are some key points.
1/ The Xmas Bubble in England is between 0001 hrs on the 23rd December and 2359 hrs on the 27th December. That is the maximum time for the bubble to travel to get to each other and to meet up.
2/ The Christmas Bubble in England applies to ALL Tiers for those dates.
3/ If you are in Tier 3 before and after the bubble dates, you are closed again, and this includes New Year.
4/ Only self-catering can have Christmas Bubbles staying overnight for the nights of the 23rd to the 26th December inclusive. So four nights. Guests can stay in hotels, B & B's and guest houses only so that they can go and meet their Xmas bubbles in the daytime, but they can only stay overnight as a single household.
4/ Anyone from any Tier can travel during the Bubble period to, or through, any other Tier level to form a Xmas Bubble.
5/ Exceptions for all Tiers is that guests may travel on 22nd and 28th December to enable bubble to form if they are from Northern Ireland (and give them the full Bubble period).
Full details here. www.gov.uk/government/publications/making-a-christmas-bubble-with-friends-and-family/making-a-christmas-bubble-with-friends-and-family