Kerry, I'm getting my rear axle relubed tomorrow, so I'll get the mech to check on all that is there.
w126, I'm replacing all 3 belts tomorrow too, but the squeal cant be due to the belts as it only comes on when the car is moving. With the engine running in the stationary car, there is no squeal. I still have yet to pinpoint the cause of the warm start problem, but as I was advised by Stevebfl and JP, it is more likely a vacuum problem rather than a fuel problem. I'll get my vacuum lines and valves checked tomorrow, and according to Steve, there is a suspect called the decel dump valve which might be the cause.
Listened to the car again this morning after a 20 mins drive, the squeal is definitely coming from the front!
1979 W123 (200/M) Midnight Blue
1983 W126 (280SEL) Dupont Deep Black (Previously Pristine Silver)