Thanks John and Steve.
I've already got the two small BMW 'O' rings, also now, the ALU1403 washer for the sump plug.
The transmission fluid I've got from a local MG Rover parts supplier who also, incidentally recommended the 5W/40 fully synthetic against MG Rovers own 10W/40 semi synthetic, this was also echoed in the BMW parts place as being the better choice,
.
As you say John, the level plug washer is elusive, it doesn't appear on their computer system at all as an MG Rover part, however, they do have a Freelander part which is the plug and washer in one packet which their MG Rover guy of many years experience says is the same, I'll let you know.
-John.