Combining UK company with Belgian entity

Are there any benefits to somebody based in and mainly operating in Belgium to have both a UK and Belgian company?
This to utilise things that are "better" in one country, the differences in tax year, or just having several items of the same type (like an iPhone).

If I start now for example, and I can't invest this year, I wouldn't have to wait one year for write-offs. Also I could more profit to the UK at the end of the year, and back to Belgium at the end of the UK tax year.
(Would not having a UK VAT number be a big problem?).

(I know I would need to have some connections to the UK, and that personal taxation on profits would be the same).

Are there better forums for this? Accountants that know this combination?