Classic British Flight Sim

Maybe the cleaning lady wanted to hoover under the tyres.

You're right that the cradles seem to be Vulcan specific. I'd think that they got those off the RAF when they got the airplane. I'm sure the RAF had several sets of these and as they're not longer of use once the plane's gone, they may have given them to the museum or just charged scrap value for them. It's not unusual for the DoD here in the US to send a set of maintenance stands and fixtures with airplanes they're donating/loaning to museums to help ensure that the aircraft are properly cared for. This is especially true for aircraft on loan from the US Air Force or US Navy Museums as they have required maintenance standards or they will take the planes back and give them to a museum that can/will take care of them.