Thank you, TheCorbyLoon.
I thought that there ought to be a relevant Royal Proclamation but I couldn't find it.
(However, since bank holidays have no legal status whatsoever in employment law, other than for those who work in the financial sector, it's largely irrelevant as to whether any particular day is, or is not, designated as a bank holiday. The fact that most shops will be open tomorrow is evidence of that).
Chris
PS: What are you doing up at this time of night? Following the cricket, perhaps?