But taxes on dividends got higher and higher in recent years.
You can still work for years in the UK, accumulate money (or real estate / other investment) in the company - then you move to Dubai and withdraw dividends tax free.
You end up paying 19% corp tax rate on your income that you can access only after you're done with the UK - which is not great compared to lower taxed countries in Europe (Malta at 5% being the best), but you get access to the London only jobs which pay a bit more (even if now that's not really true in a post remote working world).
Definitely better than getting equivalent salary and being forced to stash money in a pension you'll see when you're 60 or pay 40% taxes
The customer gets a refund, but has to charge their own customer VAT on the full amount of the goods they are selling, so the VAT accumulates until it is paid by someone who cannot claim the VAT back
That's why it's called "value added tax" - each supplier in the chain generates VAT on the value they add.
Tell that to all the contractors that had HMRC tribunals pre reform.