I'm not really the best person to give a reasonable comparison between south-east England and Belgium, I just dislike the breakdown in parts of society in the UK, there is a huge underclass there of people on benefits, it creates alot of resentment among those middle income earners who are just about able to look after themselves and their families. But mainly we like it better here because our children have more opportunities to do sports after school, more freedom, more autonomy.
If you are living in Belgium but being paid in a different currency, you can opt into the social security system, that gives you entitlement to health care. You still pay monthly health insurance too, it is not huge though, we pay under 10 euro a month for a large family. My employeur includes optional hospitalisaiton insurance as part of my contract, so anything not covered by basic health insurance gets covered by the hospitalisation insurance.
Family life and values are still quite strong here, as far as I can see alot stronger than in the UK. Fathers where families have split in the main play an equal part in their children's life, it's the norm to have 50/50 care, "family" is very very important. It sounds old-fashioned but I like their values. UK does seem to have lost its way in this respect. I'm sure Belgium may go the same way eventually.
The tax system here can be quite cruel to single people and families with just 1 or 2 children, paying 50% tax ans social security in this situation is not unusual. 3 children + is quite advantageous, it's no surprise families with 3 or 4 children are quite normal here, not only do you get more salary tax free but you can off-set an awful lot of child-care to reduce your tax bill. I have a tax allowance of somewhere like 20k tax free per year, would be lovely to make it to my limit!!
No idea if we are here long term, that is up to PM of the UK David Cameron who seems to have a vendetta against UK government employees based abroad and seems hell-bent on sacking a fair proportion of us.
Seriously check out the fact that USA does NOT have double taxation treaties with several countries in the world. For example, we are paid from the UK, we pay our taxes there, we still have to declare them here, but we pay no tax on our UK income to Belgium. This is because of a double taxation treaty. Whereas for US residents, money from US companies is taxed on a world-wide basis. If you are living in a country where teh US has not signed a double taxation treaty, then you pay tax again on the same income to whatever country you are living in. I'm no expert, but that's how I understand it works.
Oh one last thing, child benefit here is exceptionally generous to families in Belgium for families with 3 or more children. We get over 800 euro per month, it pays for our grocery bill. We could also opt for the UK child benefit, but that would give us only 300 euro per month. So that's another reason why I cannot say the UK is a great place for families to live, it's not for anyone with more than 2 children.