There are a few companies out there who advertise the removal of dpf's and reconfigure your ECU to suit,have you tried a good intake/cat cleaner? Cat's are usually very expensive and before renewing I would be making sure all other possibilities are looked into,a lot of problems on modern motors are down to a lot of town driving/short journeys and your warning light can be brought on due to a number of reasons,ie misfires/filters/plugs etc. Good luck.
cdc
March 2015