Travel medical insurance is a common occurrence for Canadians. Because we travel down south so regularly.
A few ins and outs of the medical part (and this is in general, not anything to do with the UK)---
*First, you might never need to utilize any of these points. It is simply for your information, it is not to scare you by any means.
*One of the most important choices is to fully reading your policy - or better yet ask to do that ahead of time so that you completely understand. Do not take a company's - or any broker's - take on the policy. Read it yourself.
*The biggest issue in understanding policies is most do not cover pre-existing conditions. If someone in your party has a serious - even a not so serious condition - search out for a policy that has coverage for pre-existing conditions. They are usually more expensive and not as common. Also, there is often a monetary limit on claims for pre-existing conditions. Just know that.
*Also know that insurance agencies can make the call on these pre-existing conditions. Their own call. For example, someone can have dementia and can fall. They might have fallen because they simply tripped. However, it doesn't matter from the insurance agency's viewpoint. They are known to tie in outcomes to one's pre-existing condition.
*Know your own medical record. They have complete access to it if there is a claim. And a change, any change, in medication can be a big deal with pre-existing policies - sometimes there are clauses about the policy being null and void with changes in medication. Just know your policy.
*If there is something that you need to claim for do know most policies state that they need to be phoned immediately, when using their coverage. And some policies state they must okay certain medical choices/scans. Obviously this goes right out the window if someone is unconscious. And not all companies are so strict about it, just know.
*Watch your dates on policy. Some do not seem to count days as simply as we do, insert smile. I would buy one or two days beyond. I went to extend a yearly policy once and was told it had already expired that day. My math was not their special math on the number of days on vacation.
*Air ambulance and ambulance coverage are a big deal. Make sure that they are in your policy. A lot of stories of people being stuck with payments are from these possibilities.
*Always know that insurance agencies and medical institutions play shell games with each other when settling. Always know you too can negotiate payments when they are billed to you, just like they do with each other - if something is outside the policy. Even if someone doesn't have coverage, you can do that as well.
I know this all seems like doom and gloom. And many people never have an issue when needing to make claims, there are some great companies. Heck most don't even need to make a claim. But unfortunately I did and it wasn't pretty. My father was travelling in your country and I thought he was having a stroke, begged him to get immediate medical assistance. He had glioblastoma multiforme, brain cancer. I learned the ins and outs of his policy and the insurance agencies very quickly and over the next year fighting with insurance and those looking for their payments. If you ever need to make a claim the best advice, if anyone bothers you with bills/phone calls, is to tell those trying to settle a bill to stop phoning and deal with the insurance company. And vice versa. Often the insurance company is arguing with the providers about their invoice, and not paying. There are also ombudsmen to challenge a decision.
You'll probably never need an ounce of this information OP, but it never hurts to be informed.
Have an absolutely wonderful vacation.