Family, basically. Yes, the social charges are... shocking. 17% on unearned income, from the first euro, where neither the UK nor Canada charge on unearned income.
Still, from that chart, after the social charges are done there is little actual *income* tax if you have a couple of children.
Plus, where we're going, you can get a 3-4 bedroom house possibly with a second building with another room or two which could be a gite, for 140k Euros, maybe quite a bit less depending on how much effort you're willing to put in renovating. A 'normal' 3 bed in the UK would cost us close to double that. So that's a big chunk which can stay invested to offset the bloody not-tax we're paying for nothing on investment income (literally nothing, you get no entitlement or benefit in return - no pension, no healthcare, nothing).
The UK doesn't see the RRSP as anything special, but when you convert to an RRIF you get zero withholding from the Canadian side. You pay tax on dividends and on capital gains in an RRSP, but nothing as money moves out of the RRSP (but of course Canada takes a cut then and you can't offset one against the other). I haven't quite figured out if you pay tax on divis and cap gains inside an RRIF, I'm actually waiting for HMRC to get back to me... not that it matters now.
It would be a 7+ hour drive from Belgium to visit family, and homes there are probably also in the double range. Probably not worth thinking about though I'll look at least a little, thanks.