Nice, subtle panel line work Andy.
The interior colour of the wheel wells, doors etc on Hawker aircraft was normally 'silver'. However, I have seen a short film clip, and one colour photo only, where the wells and only the inner (small) door appeared to be the cockpit grey green, but silver seems predominant.
That said, in some B&W photos, the inner face of the main gear door looks like it might be MSG, and if so, probably re-painted at a MU or even in the field.