V50 Engine 2.0D : DPF or Air Mass flow fault

[Mikesm11]

Hi,

First post. I have a V50 2005. Having just covered 1800miles across france I got within 2 miles of home when it went into Limp Mode. Fortunately I had made it back to UK so called RAC. They checked codes and reaad 2 faults
1. DPF Differential Pressure sensor intermittant fault
and
2. Air Mass flow error reading.

They reset and I drove home ok decided to replace the cheaper of the two options and ordered a new DPF Differential Pressure sensor from GSF collect Monday, but car as now gone into Limp again. When i fit new sensor will it reset itself? Anyone have any idea if which code is most likely to cause limp mode? or perhaps I should replace both.
Is the Air Mass sensor the unit coming from the air filter housing connecting to the large diameter air intake pipe?
sorry for all the ??? hope someone can offer advice.

Mike