Re: Isn't it ironic
I'm not a lawyer or an accountant, but:
1. This is an international site. Not everyone reading here is in the UK. I'm in Canada, for instance. There are lots of Americans here too, and the IRS is notoriously...grabby.
2. It's not just about you paying your income tax. Various taxes your employer pays or credits they claim might depend on your physical location or tax residence (which, as you note, aren't the same thing).
3. Your employer might have rules and policies that, while they aren't laws, you're still going to have to consider. Mine, for instance, only allows you to work from another country while getting paid at the scale for your "home" country for two years. After that your pay gets changed to scale for whatever the new country is, which if you're in the Caribbean is going to be "lots lower", most likely. And if you don't tell them you moved, you're in trouble.
I'm not saying anyone shouldn't do it, I'm just saying it's not as simple as "get visa then bog off to beachside paradise". You're at least going to want to tell your employer about it first, and yes, they *can* raise hell if you do it without agreeing it with them, unless it's somehow written into your contract that you can do it.