There is no specific law against travel within England, regardless of tiers.Just to clarify once again if you'll forgive me... the 'do's and don'ts' say you should not travel outside your area or stay away overnight (in tiers other than 4). Is this still guidance or the rules? Given the earlier reported debacle at Southport, might one encounter trouble attempting to rock up there, and stay alone in private accommodation for a few days?
Residents of tier 4 who look to travel out of their tier May (or may not) be in breach of the requirement to stay at home unless they have a reasonable excuse.
Visitor accommodation is to remain closed in tiers 3 and 4 excepting certain categories of person.