08 Plate Freelander 2 TD4 Sport - Gear Change issues & Lack of Power

I'm writing this on behalf of my eldest son who is not a member on here (but have told him to join). He was driving home from Bristol to Falmouth last week and was finding automatic gear changing was not happening as it should. The vehicle would stay in high revs before changing and then going up inclines would drop gears and lose power. He finally 'broke down' at on the Bodmin side of Launceston. I went to collect him and we tried to start the car, which is would but had no power when accelerator depressed so would not keep running.

We had it recovered to Penryn and now waiting for someone to look at it to diagnose what they think may be wrong although it has been suggested it could be the gearbox itself.

Any suggestions would be gratefully received as a starting point as to what to investigate.

It needs codes read on diagnostics, it it might be as simple as needing a fuel filter, unless he’s filled it with petrol?