I have a similar issue and assumed it was just a quirk of the td5 as I am used to older pre electronic diesels. I have exactly the same issue, starts first time every time but takes somewhere between 5-10 seconds before you can rev it up properly. If you do pull away in this time have low power and revs then it remedies itself and is back to full power. I had got as far as working out it was a fueling issue and it is not delivering enough fuel until it has settled after this initial period. I will try unplugging the maf and seeing if that makes a difference. I will also check the injector loom again although this was checked and was clean about 6 months ago and have had the issue since I started using the vehicle. I "get around" it by starting the engine as soon as I get in the vehicel and then by the time seatbelt is on and phone is plugged in satnav set etc it has settled and is good to go at full power.