Poor starting from cold engine (not weather)

Hello, 

I've come back to a Ford focus after having a golf for some years, the only issue with my Focus is it doesn't like a starting after it's been sat for a while, I.e a cold engine 

It's a 2009 2.0 tdci Auto, same engine as Peugeot and volvo I believe? 

Had a leak off test nothing reported, 

Recently changed the fuel filter, nightmare to get going again but did it

New Higher power battery

No fault codes at all 

It's really confusing as I think it could be fuel related as it sounds like it's run out when trying to start then coughs in to life and runs fine. 

I know it's not likely to be glow plugs as the engine doesn't need them unless it's very cold currently it's + 23 ish degrees 

Has anyone else had this or a similar problem? 

Any help would be greatly appreciated 

Ian