From AAISP status page - https://status.aa.net.uk/1868
Special Holiday Rates
We are pleased to confirm that customers on our standard units based tariffs will again benefit from a Christmas special rate between Christmas and New Year:
* The three normal working days between Christmas and New Year will be a Christmas special rate which consumes no units regardless of the amount of usage.
That is 27th Dec, 30th Dec, and 31st Dec.
** The 28th Dec and 29th Dec being normal Weekend rates.
*** The 25th Dec, 26th Dec, 1st Jan (and for lines in Scotland, 2nd Jan) are also at Holiday rate.
The special 'Holiday' rate is the same as weekend rate.