Hi. I had similar rough idle...had to idle for 2 minutes before moving off or car would stall on first brake application. When warmed up after 30 minutes i had similar problems.
My SOLUTION was the OVP (Over Voltage Protector)....it was faulty (no obvious signs of this)...replaced this with a good second-hand one for £20....ALL symptoms sorted! Idles perfectly etc!
Good luck!