Your 1.6 will have a dual mass flywheel for sure, all Ford TDCI do now.
The filter you're concerned with is the Diesel Particulate Filter (DPF) and is much maligned on the 1.6.
I chose a 1.8 specifically6 because it doesn't have a DPF, when they clog you will get reduced power and performance issues.
There are a few things you can do about this-
1, Remove the DPF but leave the canister it sits in so as to pass your MOT.
2, Give it a good run on a motorway in 4th so as to force a regeneration (burn the crud out)
3, Something I'm having done to my car on Thursday, a Terraclean service, where the engine is run for an hour on a special fuel mix to clear out all the carbon from injectors to exhaust. If you watch Wheeler Dealers you may have seen this being done on a Jaguar that would have failed it's MOT on emissions but after the clean it was well under the pass limit.
It's available for diesels at various places around the country, and even though I don't have a DPF, there is still the Exhaust Gas Recirculation (EGR) system that will carbon up after a while and stifle the engine too.
Some have blanked theirs off but you will tend to get a fault code popping up occasionally as the sensor in the EGR has been bypassed and throws a wobbly occasionally but doesn't affect the running of the engine and can be deleted when it shows up (and especially before an MOT).