£1420 for a new DPF, £265 is labour which means the DPF is £1155, seen them online for £700, unless there are sensors like you say.
Sensor is £50 if it's the same as my Seat was. That price is actually pretty reasonable. Main dealer quoted me £2100 for my Seat, quite likely same part as will go on your Audi.
However I went the non genuine part route, that was £700. But I have a warning to heed, the non-genuine part did not fix the problem and because of this I ended up having to sell the car at auction at a much reduced price
I think the car had a underlying fault that caused the DPF to fail (if it did actually fail) and look like it needed replacing. This was confounded by fitting a non-genuine part as Seat blamed it for the fault. It may have been fine but as non-genuine part it could have been causing issues. I suspect the underlying fault was with the ECU as the pressure and temp readings in diagnostics were all over the place.
In the end, I spent £1000s and got nowhere. So before you commit to changing DPF, get a decent diagnostics person to look at the car.