Thanks for that message/post. I had bought a new filter as part of renewing parts but was thinking it might be a sensor - I’ll fit the filter tomorrow and report. Your symptoms describe mine. First time I’d seen that hatch under the seat - it was like finding treasure, I gave the rubber bulb a squeeze!On the 1.5Dci the filter is under the car, easily accessible and the hoses are a push fit so its nice and easy to swap out, the filter does need to be primed. theres a hatch under the right hand seat, you just squeeze the rubber bulb and can feel when its done as the bulb goes solid.
i had problems with poor acceleration, random power loss particularly going uphill, spluttering, engine light coming on and off, had it checked on diagnostics and it came back with all sorts of problems related to the fuel system injectors, pump, etc etc.
all cured with a new filter.