I was PNF'ing the 340 with the nosewheel steering problem. A small shuttle valve in the system decided to fail as we slowed through 50 or so knots, making the nosewheel steering inop. The aircraft was very light (we'd only come from LGW) and so taxiing on power and differential (hot) brakes was a little tricky, but we got it onto the outer after a fashion. We were towed in from Block 37 to stand 338. Thanks to all who helped out, including the fire service chaps, and sorry for the disruption we caused!
Scroggs