Some clarification on car insurance. Someone else posted:
"Most people don't realize that their auto insurance coverage goes with them overseas on car rentals. You'd have to check with your agent to verify if this is the case.
The credit card coverage on comp and collision is usually secondary to your primary insurance carrier. So why do most people that have full coverage insurance and a credit card insurance supplement want to pay extra for CDW?"
I have been told by two different insurance agents (one is also an attorney, the other a past VP of an insurance company before retirement) that the first statement is not true. Read your policy carefully.
So "The credit card coverage on comp and collision is usually secondary to your primary insurance carrier." is not true either, unless you are inside the U.S. and your insurance is a U.S. carrier with you as a resident of the U.S.
So, make sure you have an adequate car insurance policy bought through the rental agency to cover damage to the car or theft of the car. A few hundred bucks (or pounds) is nothing compared to the damages if you accidentally hit someone on a bicycle and they are disabled for the rest of their lives. (And after all, you'd want them to be compensated, and their medical expenses taken care of.) Or the expense of the theft of the car. Yep, if you're not adequately insured and someone steals the car, you are on the hook for the entire amount of the vehicle.
Make absolutely certain you're insured for every possibility. Better to be over-insured than under-insured.
Personally, I would go with trains, buses and regional tour companies instead of renting a car, but that is just my preference. If you check over on the Wales Forum, there have been several small local tour companies mentioned from time to time that do an excellent job of taking folks around to the castles and towns of Wales.
