Hoselock retractable hose (Bramfield SG14)

A Hoselock retractable hose which I think it's 30 metres long. Includes bracket to fix to wall/post. Pulls out fine and goes back in but the brake/lock mechanism seems to have failed so you have to keep a firm hold of it or it will rewind itself when you are using it!! Maybe fixable for a handier person than me.