Wayne's got it! The second shot, looking down and in to the Spit cockpit, is more accurtate, as the first one has been affected by the flash. To get this colour, which you can get as a ready-mixed paint from some companies, mix Humbrol matt Dark Green 30 with white, and add a smll spot of yellow, or blue. Sounds strange, but they both work, as the shade could vary from aircraft or paint batch, sometimes looking more like a light greenish grey.
By the wheel stanchions, if you mean the undercarriage (landing gear) legs, it depends on the aircraft. On the Spitfire, depending on Mark number and date, they were generally the colour of the underside camouflage, but later they were a silver-grey colour, in both cases with chrome Oleos. The latter is the telescopic 'shock absorber' part of the leg, normally, on most aircraft, at the bottom.
On your Beaufighter, the undercart legs were mid-grey.