Thanks for all the comments. I was obviously flying IFR from Liverpool since it was night but actually received a VFR clearance (a mistake?) - not SVFR or IFR - with no flight plan filed. I understand now why I didn't get charged from Antwerp since I could fly night VFR there. I still don't believe I should pay a charge when no service was provided but I think the answer is to get a twin under 2000!