Mine idles at 950rpm which seems a bit fast to me. I'd expect a diesel to idle at about 750-850 rpm. Driving in slow moving traffic is sometimes a bit awkward as using the brakes just pulls down the engine, especially if in second gear. Moving slowly has to be in first gear, or constant use of the clutch, neither of which is ideal.

Can the ECM be altered to slow it down a little? Has anyone had the same issue, and has anyone done anything about it? Also has anyone had theirs slowed down and found that has caused other problems?.....

I don't think it's adjustable. Normal idle is 900rpm, or thereabouts. The answer is to use first gear if the traffic is very slow.

Mine rumbles along at 850 to 900 ish hot idle, which is great in traffic jams, since it means I can run up to about 20mph "feet off". 950 sounds like my cold idle, which has me wondering if your car is actually not properly cancelling the cold start mode.

I did replace the coolant temperature sensor too. I did wonder if it would alter the idle speed but it hasn't......