[Colin D5]

Hi all, this is my first post to the forum =]
I've owned my 2002 V70 D5 163bhp for the last 7 years, its covered 70,000 miles and have had no problems with cold starting before. However recently when its first started in coldish weather it runs rough for at least a mile and returns very poor economy whilst its cold according to the OBC. Once it warms up its as efficient as normal and runs fine.
Ive had the glow plugs changed and its been for an oil and filter service but this hasnt helped.
The car is kept in a garage overnight as it always has been so I have no idea whats caused this problem. After searching the forum Ive found a few things I guess that it could be but I was wondering if anyone had a better idea?
Could it just be the fuel filter or is it something much more costly like an injector or the MAF ( is the MAF and IAT integrated as I cant seem to identify the IAT)?

Many thanks, Colin =]