(Added: Maybe you just want to know hidden gems and stinkers!
Not necessarily a treatise on cruise vacation planning.
If so, just skip.)
When you thought, “British Cruise,” was there anything /place that came to mind?
On a first visit to a place, I often do a Hop On Hop Off bus to get a broad view of a lot of the city. Going to Glasgow from Greenock can be done by train. Edinburgh is a fair distance from the port of
Queensferry (I see your port would be Greenock for this).
Are you an explorer, equipped with a game plan (or a plan to just discover), or do you want a guide talking at you all day (those are extremes - but try to think of your travel style, if you have one).
Liverpool does = Beatles. But it also had an early sewer system. Now, “ferry crossed the Mersey…”
Do you enjoy tying songs or references to places you see?
A good walking tour can point out things you wouldn’t think of. As can a bus ride.
Do you want to do a lot of riding or would walking better suit you (or be a challenge)?
@Retiredcruiser seems to have some idea of what interests them.
If you are interested in the Titanic, look at Cobh.
In addition to looking at what
DCL offers, go to TripAdvisor or Viator (same company) or Shore Excursions Group to see what else is offered - and just things to do.
Not everything you want to experience is necessarily bundled into a package excursion.
Sometimes, a port can be enjoyed with a walk and seeing the area.
I have watched a lot of YouTube videos regarding cruises and port stops. Do a search for your ports and you will have lots of viewing choices. You may find a channel that presents the info in a way that you enjoy. Don’t be afraid to fast forward to the point they are off the ship (skipping them eating breakfast…). A lot of these are going to be people who did British Isles cruises.
Obviously, you have already begun your research - getting ideas from your fellow DisBoard members.