About 67000.

Also passed the MOT with no issues and was serviced about a month ago. 2 weeks before the injector seal change.

The 2.2DCi auto (Sp Tourer) will do 40 - 42 mpg on the motorway and at worst ~37mpg (the official average) on shorter runs. The manual version should do even more. assuming that the cam belt has been set correctly and that there is no gasket problem to deal with, it sounds like you need to clean (and check) the EGR valve and possibly the "throttle chamber" where it sits, which usually needs a good clean every couple of years. It is not a difficult DIY job if you are mechanically minded, if not you will need someone who knows what to do to get involved. It makes a material difference to the performance when all is reasonably clean in that area. The signals that a periodic clean is required are when you notice slower pulling away accompanied by quite a puff black smoke and, of course, (much) worse fuel consumption. This engine benefits from hard work and every week or so you need to pull away fairly sharpish to clean the slight soot that builds up around the EGR valve. The good news is that if you look after this engine, use fully synthetic 5w/40 oil and change it at 9k mls or annually if less mls (to keep the turbo well lubricated) , it will go on and on and need less EGR valve cleaning! at 67K mls your engine is just becoming run in and should go very efficiently at higher mileages. BTW you need to consider changing the glow plugs ~70K mls which costs £45 ish for parts and is simple to do ( if you know how)!