Regarding Leon DPFs, there is an upgrade to the ECU firmware from VAG that will apparently heat the DPF up quicker and clear it quicker. Not sure what years have it/don't have it.
I happened to find this out from a VAG independent. I then asked the Seat dealer to do it while it was in for a service (VAG indie said they couldn't do it). The dealer didn't offer it, e.g. by saying "BTW there's an update available", had to ask them to check.
Seems to work, if DPF light is on it will clear quicker than before and under lesser conditions. Used to have to be a constant motorway run to do it but it'll do it on A roads and shorter runs now.
Edit: Just to add my car's an 2007 2.0 TDI FR