Forward contract for exchange rates


I use an company to receive and send money in USD. I also use them to exchange USD to GBP.

They are offering me the option to lock an exchange rate.

They ask if I have considered forward contracts to secure an exchange rate for an extended period of time? With the USD to GBP rate at two year lows, it’s not a bad time to be thinking about it. As a quick overview, your average rate last year was 1.3459, you could currently achieve a forward rate of 1.2333,

Is it permissible to do this?