I am a US Citizen, so I can be in Schengen Area for 90/180 days. Did that May 1-Jul 30. So I can't go back until Nov 1.
I can be in the UK for 6 months. Southern Ireland, or "Ireland" to the rest of the world, is a separate 90-day Tourist stay. I'm good to go to Belfast, being part of the UK, so I could take a Train south to Dublin again -where I made a fun movie last time.
Cities I've been to in England and Wales: landed once at Gatwick, once at LHR, then Cardiff by train (made movies), Wrexham, Liverpool, Holyhead, Preston (made a wonderful movie), Leeds (ditto on a movie), Manchester, Birmingham (movies), Stoke on Trent (movie), Derby (movie), Northampton, Nottingham (movies), Reading, Bristol, East London (Barking) (movies).
The British Beef - Naked Muscle on Home DVD and eBooks.
Those are the cities I stayed at least one night in each. I've been in the UK twice before, 6 months each. This is my 3rd, 6-month trip. I'm in Liverpool for sure for 5 weeks. Maybe longer. Depends on lodging costs. I went to Dublin by Fast Ferry on my first UK trip. Want to go back, but lodging is astronomical by US standards. Better with the fall of the GBP and EUR.