just an update really in the hope that it might help others with similar problems...
smoke has stopped altogether now. i replaced the filler neck seal to be on the safe side (as described in this thread) and have been under the bonnet every time the car has stopped after a journey. have been cleaning up any excess oil i can see along the way, although i think the power washer got rid of most of it, and can only assume the final oil smoke was old oil that had sat prior to gasket change. worth noting that since the weekend i've done about 200 miles which presumably has burnt it all off.
im sure passenger side gasket wasn't quite as snug as it should have been after initial change of gaskets, but i repositoned the offending one again (as described on this thread), cleaned up cam cover area and engine bay, as well as underside of car, replaced the oil filler neck seal and now everything seems to be a-ok!!
thanks to all for advice along the way, hopefully that's the end of it.
now... on to the oil cooler...
