Where to buy dpf for 2012 Outback

Hi all, my friend has got a 12 plate Outback and apparently needs to buy a new dpf for it, the car was in the local garage a few months back with dpf issues and after charging around £1400 a sensor was replaced and the dpf was cleaned as it was blocked solid (other tests and work were done) and the garage owner said he thought it would be ok but if not then a new dpf will be needed and apparently you can only buy a decent one from Subaru, he wants to buy one that will last so does anyone know of another supplier that won't charge as much as Subaru please?

Thanks.