X5 E53 3.0D - Won't accelerate and stays under 2000rpm...

[j9mm0]

This has happened twice now. I pulled off the drive and found that there was no power and it won't accelerate. Foot flat down, it stays under 2000rpm. I stopped for 1 minute and restarted and it seemed fine again.
This has also happened again recently, so thought I'd ask for some advice.
INFO:
I have recently had an oil service (2wks back) and inspection I (Friday 31st Oct). When I had the oil service the garage informed me that the X was awaiting an Inspection I which was 1100 days old!... I've only had the X for just over 1 year and the dash has never shown this. Hence the reason why the services are so close together.
The lack of power was on the Saturday after the Inspection I and Monday night (4th Nov).
Any advice would be appreciated?
Thanks.