The ash mass needs resetting & a regen calculation test drive for the lights to go out.

If your scanner has no functionality on this system in expert mode MVB 067 etc...you may get it to reset by driving at a steady 2000RPM for half an hour or so on a motorway, but there may be an underlying fault which generated the fault in this system in the first instance.
i.e Throttle valve / EGR / Differential Pressure Sensor / Software issue / Glow Plugs / boost pressure control / exhaust gas temperature & so on.
In which case this vehicle may return soon if the cause of the initial fault is still present.

You can't clear a DPF warning on these when the DPF has been replaced until the PCM has been told a new DPF has been fitted & it has seen the relevant calculations from the relevant sensors to confirm a new DPF has been installed.

VCDS is the cheapest way to get in deep on VAG models. Less than 300 quid with tech support & a excellent website with guidance on a lot of DTC's that are common offenders in VAG systems.

I'm with Liam & Dave and not trying to appear elitist, but: Replacing £1500 quids worth of DPF with no knowledge on the subject & without asking on here of potential causes & cures before you blew the customers money is beyond the realms of human decency.

I would have emailed you some info specific to VAG if you had asked first.

For the customers benefit I still will if you think you need it?

Initial diagnosis of DPF issues on VAG is carried out in the measured value blocks and based on the DTC set, there is no necessity to remove the DPF & start blowing air into it, particularly if you have no concept of the internal structure.
It'd be a bit like using joke binoculars where you are left with black rings around your eyes.

There is a lot to be said of the theory that you can often halve your diagnostic time on a system you are unfamiliar with by reading about it's operation & function for an hour.

The time spent removing the DPF etc could have been bypassed by searching or posting here first for info,or searching the ross tech wiki or google for the DTC by inputting "08194".