I did a trip to Ireland in 2000 for 45 days before Digital. I took a Contax 645 kit and some Pentax 67 gear with the Pentax 67 to Contax 645 lens converter. Double bodies of everything, polaroids, film backs, etc..
It all went in a LowePro Roller. I have since switched to ThinkTank which by far are the best rollers around.
I took a shoulder bag to cary the things when I was away from the car. The great thing about the UK is that you have the ability to have a car and leave things in the boot i.e trunk. I bought a chain harness that would wrap around the bag with a lock and lock it to metal bar in the trunk. Lightware and Lowepro made it, not sure if they still do. A good pair of bolt cutters would take it off, but for the guy just walking up no way.
Also, all the B&B's I stayed at were amazing as far as watching gear for me. It was like you were staying in a friends house.
If you will have access to a car make sure you rent one with a proper trunk not a hatchback. Out of site out of mind. For day to day traveling the roller is great. Just carry an empty shoulder or waste bag and take gear as you need it.
Have a great time!