Citroen dispatch 2.0 hdi slight miss on start up ??

[crewieboy]

when starting my dispatch it sounds and feels like it is slightly missing ,it starts 1st turn of key but doesnt seem to tick over correct ,as soon as you give it some revs it corrects itself and ticks over smooth ,it runs spot on after pulling away its just this initial start up could any one point me in the right direction to solve this little niggle ? , many thanks