just picked up my new car, westfield sew cossie powered 2wd

slight problem!

whenever come to a stop after trip out, have a look at engine and there is a puddle of oil on top of rocker cover at one end... cam cover end

also seems to be oil coming out from top of dipstick...

have replaced oil filler cap 3 times with no joy...

seems as if it comes from the cap...

why would this be?? breather system problem maybe??

bottom end sounds fine, no knocks...

rebuilt 20k ago... starts from cold fine... just seems to have this problem??

any ideas/remedies would be appreciated!!