Not uncommon in the UK. Much less so pre brexit as so many companies moved there operations out of the UK. But yes 1000s of people I the UK worked in the EU on and of related to their job. So not a majority. But far from uncommon. And ferries to the EU cost about were very often cheaper then trains in the UK. Heck even plans often are but those cheep flights don't tend to be regular. Ferries are easy ways to get to the EU cheap and often.

And within the EU land mass. The open borders make it a drive or often only a freaking bus ride. Copletely invalidating all you bullshit about how the EU ain't as open as claimed. Just because indevidual governme ts are not forced to share. Because the EU dose not remove soverienty as brexiters keep bullshitting. In no way indicates that cross border deals were not much easier then you claim.

And you while travelling to the EU was way cheaper then 500. Closer to 100 in petrol and ferry feels when booked in advance. 500 is only a huge cost every few months for the poorest in the UK. Most with an above minimum wage jobs have and will spend that hor helth needs.

So no that sort of cost in no way indicates it was rare.

Maybe you need to get out of your bubble a bit. A sizable % of people far from rich are able to spend money on thing that help them work healthier.

Close to home think Gibraltar and Northern Ireland. Further afield - I work with people who regularly travel for tasks that require an on-site presence and who have long term health conditions.

Probably more common than you think.