Moving an upright piano from Belgium to England

Unless your Piano is an actual antique, or has some extraordinary sentimental value, don't bother. Really. Don't bother. You can literally get piano's for free in the U.K. It really isn't worth the money to ship one.

Here is just a selection:
https://www.gumtree.com/search?search_category=pianos&search_location=uk...

Cheapest option - you or he hire a van with enough space for the piano and drive across. Eurotunnel and Ferries are quite cheap for a 2 day trip and can also take other stuff across or use it as a weekend to catch up

Yes, I agree with JT but you may find that Eurotunnel will only ship the van as freight, the ferries will take it as a passenger vehicle though.
Whatever you do, make sure that you ship it before 29 March, you could end up with some very nasty surprises if you leave it after that date.

It’s not commercial so you can use Eurotunnel. Dockx does good van hire. Might be worth getting one with a tail lift or ramp. Hope you have some strong helpers.

If you're going to hire someone for the job, remember that you'll have to pay for two people at both ends of the job, as one isn't enough to lift a piano.

If you do decide to do it yourself, have you thought about how you're going to move the 150 - 200 kg piano to the van, lift the piano up into the van, and off again once you reach the UK, and then move it into the house?

Unless you get a van with a lift, and have access to at least two strong people (at both locations), it's going to be a problem.

Please make sure the piano is secured properly. Upright piano's have a high centre of gravity and will topple over when you go round a corner.

etc. etc. etc.