Vauxhall Meriva Diesel Particulate Filter (DPF) Problems

I have a code 55 and an amber filter(?) symbol displaying on dash. Mechanic said it was a sensor for a clogged particle filter and has cleaned filter & reset the fault. Keeps coming back after some hours/days .Recleaned filter a few time...

Code 55 and Amber filter light flashing for blocked dpf ,but car not in limp mode and drives fine ,have blasted up motorway and it still come on any idea,s have put dpf cleaner in tank as well .

Car randomly looses power , not so bad if revs kept below 1500rpm , Struggles to overtake other vehicles , it also randomly cuts out, restarts straight away . Egr valve and cooler replaced, DPF cleaned, I think it has to be a sensor iss...