I've been making lots of transactions using PayPal "Friends and family" free of charge payment. If, like me, you are in the Euro zone and wish to pay in GBP, the only "fee" you'll have is the exchange one. But, if you pay in Pounds and then convert it back to Euros onthe other end (or the other way), then, you'll pay extra stupid conversion fee. Using a bank transfer will be the same as there always will be exchange fee.
What I don't understand is why you paid in Pounds when the other side asked for Euros ?!? You should have paid directly in Euros and save time.
Next time, if you want to use the fully insured PayPal payment, ask the seller to send you a payment request and add yourself the extra fee by the "Friends and family" system : this way, it will be hassle free.