Yep, sligthly higher at Nieuwpoort & Blankenberge at the Mo +- 10% but Brugge should be no problem ask Luc at Flandria Yachthaven to give you some help on fuel if you are there!
The Ciggies & Boose you buy "Duty Free" is not legal to bring back to UK or to any other EU country, try arguing with the Dutch Customs at Flushing. Ok if you are leaving EU waters.