Dpf regeneration

[taxipaul]

Hi , I've been searching this forum for hints that might help me but to no avail. 

I've a 2018 1.6tdi octavia with big miles on the clock.

I had issues with the dpf 3 years ago & had a new 1 fitted by skoda.  Car has been in limp mode with fault lights on & off for about a year now ( no power,  burning oil etc. )

My mechanic has recently carried out a carbon engine flush & last week he fitted a reconditioned turbo unit ( the old 1 was carboned up & fins were sticking )  and  i had the dpf chemically cleaned in a dpf centre. Car is not using oil since the carbon flush. 

The issue now is that the dpf is regenerating a lot ( no engine lights on the dash ) & fuel consumption is up almost 50%.

My man thinks it could be a blockage in the silencer box causing back pressure forcing the dpf to keep regenerating. 

I've spent a lot of money trying to get the car right as its my work vehicle but I'm wondering if we're missing something? 

Any advice would be appreciated,  cheers.