some times when driving along, and under acceleration, the wee car misses. would this be a dirty fuel filter or new ignition leads required?

id look over the ign system first , new plugs or clean them , new leads and dizzy cap /rotor arm

Had this last week, was my lambda sensor but could equally be the above

Check for air/vacuum leaks too

From personal experience, my old 1.0l spi did the same, tightened up the nuts on the throttle body and injector and it ran so smooth :)