OK, the warning message has now gone after following @
luis Rosa and @
cancunia advice to tell Diagbox that I have fitted a new DPF Filter.
The reason I resisted this option at first was because I didn't know whether doing this would cause a serious issue with my DPF and so I wanted to explore all other areas before proceeding.
The process is as follows for anyone else with the same issue. but I would advise sorting and clearing any faults you might have first and also making sure that your DPF is actually regenerating and that your Eloys tank is not empty.
1. In Diagbox go to Repair
2. Let Diagbox do a GLOBAL TEST
3. Once the GLOBAL TEST is done, select ENGINE ECU
4. Choose PACK REPAIR
5. Choose AFTER SALES OPERATION (PARTICLE EMISSION FILTER AND FUEL ADDITIVE ADDING)
6. You will then get asked "Is the vehicle fitted with an external diesel additive adding ECU" - select the green 'tick'
7. Choose REPLACEMENT PARTICLE EMISSION FILTER
8. You will then get a message saying "This operation is to be carried out only after the procedure for the replacement of the particle emissions filter has been followed" - select the green 'tick'
9. You then get a question saying "Reset of the filter management ECU?" - select the green 'tick'
10. Then you get a message saying "OPERATION DONE"
This process just appear to reset some kind of counter which seems to automatically generate the "Blocked Filter" message when the mileage reaches about 111000 miles.