the fact is she has a british passport so she will have no probs.(unless its a fake passport). it will cost her QR-/ 100 for a 1 month visit visa (not sure if they are still doing the 14 day visa anymore) she will need a credit card to pay for this at immigration counter or just of to one side you can obtain a debit card for Qr-/ 20 (card)+ Qr-/ 100 (visa) (she can pay in pounds sterling they will do the exchange rate) from QNB please inform her of this as this is the only way they will accept payment at immigration.

cheers hope your friend enjoys her time here.