Currency conversion charge for Northern Ireland payment to UK?

[Drof]

Just sold an item on eBay and have been charged the 3.4% currency conversion (£21.65).

I'm in the UK, the buyer is in Belfast (Northern Ireland) which is part of the UK using Pounds Sterling.

Why have I received this charge?

[kernowlass]

@Drof

Thats not currency conversion, thats your paypal fee.

Paypal fees in the UK are 3.4% + 20p per transaction.