Pretty standard that you pay a premium rate in the VIP area versus normal bar, even in the UK. You've just paid €€€ for a table FFS, is it really the extra odd €1 they're adding to the drinks you're complaining about?!?!?! Jeez.
If you went to the bar in the main area of the club and bought a btl of spirit you would get it for a lot cheaper than the "bottle service" price. That is what you're paying for - the service.
I don't want to get into a debate about who likes & who hates the VIP culture - that's been done before, and we know how most feel about it. But c'mon, if you're going VIP then expect to pay more. Obviously.