seems to be lots of variations of similar problems with the GA engines, mine has a big flat spot in 2nd pretty much all the time (presumably there in all the gears but its only obvious in 2nd) and has the occasional complete loss of power and wont accelerate at all then seems to recover and run fine, does it less and less but it still does it some times, also has moments were it will run very well and seems pretty quick for a 1.4, doesnt happen often though. only ever had the engine check light once and once restarted that cleared and has never come back since. has also started to try and stall itself now, can just be idling and the revs will drop to virtually nothing but usually it recovers itself, often idles at 1100 rpm aswell but a quick blip of the throttle sorts it out.
im hopefully getting a second hand throttle body in an attempt to cure it, a full service did very little although it did seem to make the problems less frequent, has started doing the power loss thing less recently aswell but the revs dropping is something thats only started in the last month or two.