Urban Cruiser D4D In limp mode DPF?

[UCD4D]

Hello, I am new here, we have a 2011 Urban Cruisrer 1.4D, we had an intermittent limp mode issue and had the DPF and Cat prfessionally cleaned costing over £600.00 , But the limp mode came back again intermittently almost imediately, but the vsc, check engine etc lights are constantly on now and the code is still showing "DPF is blocked". During the clean the O2 sensor on the cat was replaced a pressor sensor etc.   The Garage says the EGR valve is working fine too.   The fault codes can be reset and cleared but they come back on within a few miles and car goes into limp mode again.  the limp mode only affects it going up hill and it appears 4WD is engaged constantly?   The Garage are now saying the best way to cure it is to map out the dpf.   But we won't to find what the fault is and fix it properly.  The car has only done just over 80000 miles Can anyone help?   Its so frustrating as when its not in limp mode it runs great with plenty of power.