Would 5 mile each way journeys to work and back cause DFP related issues on the i-DTEC engine?
Most likely, that isn't enough miles for the DPF to regen and dump all the carp out. Can't remember what exactly the requirements for the regen are but pretty sure you will need to do more miles and certain speed for it to regen.
Stick with petrol, far nicer, if you find a 2.4 there is flash kit for the ECU that totally transforms it.