I don't think there is any kind of wallet where you can convert your bitcoins into pounds. You can use any local crypto agent or dealer who can exchange the bitcoin with you in your local currency pounds. Even you can use of localbitocins.com where you can find the right guy who can make your problem solved. But be careful while dealing with the person whom you don't know, so only exchange your bitcoin with them whom you personally know or you approach them if there is any problem.