The Working Time Regulations 1998, PART II, Regulation 10 says
Daily rest
10.—(1) An adult worker is entitled to a rest period of not less than eleven consecutive hours in each 24-hour period during which he works for his employer.
Entitled is the key word here. I know that I can opt out of the 48hrs per week limited as per this page
You can opt out for a certain period or indefinitely. It must be voluntary and in writing.
but I can't find anything whether it's fine to do it on daily rest.