Throttle body needs cleaning, funny thats what ive been doing today and the first two posts ive read on here are about idling issues, must be the weather.

You need to clean the butterfly flap inside the throttle body, failing that its the idle control valve or throttle position sensor, use neat clean fuel or carb cleaner to do so, i recommend finding and pulling the engine management fuse out after or disconnecting the battery for a while to reset the ECU too