VAT
On the Prices page, tick This campsite is registered for VAT and put in your registration number and rate. Leave it alone if you are not registered — which is the default, and nothing about VAT appears anywhere until you turn it on.
Turning it on changes none of your prices. A price of £6.60 means the customer pays £6.60 either way. What changes is how that figure is described: if you are registered, VAT is treated as part of it rather than added to it, so £6.60 can be shown as £5.50 plus £1.10 VAT. If you are not registered there is no VAT in your prices at all, and nothing anywhere mentions it.
The trade is that a registered campsite thinking in prices plus VAT types the figure with it in: £5 plus VAT goes in as 6.00. We chose it that way round because adding VAT on top would have made every campsite 20% dearer the day they ticked the box, on bookings already quoted — and no price, quote or agreed total should move by a penny because of a setting.
The registration number is checked as you save it — a UK number carries a checksum, so a transposed digit is caught here rather than by your customer’s accountant months later. A number from outside the UK is accepted as typed, since refusing one we cannot check would be worse than missing a typo. One rate covers camping, buildings and activities: they are all standard-rated.