MASSIVE vouch for Dieze. Sold him 4.3b OSRS via UK Bank Transfer.
Pleasant and helpful guy (especially for a noob like me who didn't have a clue what I was doing). He guided me through the process and sent the money as agreed. If buying or selling gold (especially in large amounts as I did), for peace of mind, please use this guy. Thanks once again and good luck with all your endeavours,
Peace.