gas leek smell from round distributor

[skiprat]

hi all, the story so far,

i have the CNGbifuel special stepper motor fitted about 2 years ago that's still working well,

started off looking for a pesky cylinder 1 misfire, (only on LPG) occasional try slow down or shift up message.. changed coil packs round, swapped plugs round, fitted new plugs, misfire stayed on cyl #1,
in the process of doing that the pcv breather hose fell to bits, so took inlet manifold off and cleaned pcv box out (wasn't even dirty), fitted new crank case breather pipe,
i never put a new inlet manifold gasket on,
did the lpg distributor disassemble cleaning procedure.
all back together for a test run, runs ok on LPG now cyl#1 misfire has now gone. runs lovely on petrol pulls hard all the way trough revs. so must have just been a dirty distributor
but now i have a gas leek smell, moor noticeable in traffic,

so in an effort to stop the gas leek smell, thinking it must be be a bad hose, i replaced all the rubber hoses (16mm from vaporizer, and 5x 8mm from distributor using lovely stainless click clips very secure) something i would recommend doing if your hoses are original, mine were in very bad condition,

so any one got a diagram or photos of a distributor i saw a very detailed strip down procedure on a Swedish forum? but i cant find it now, i did notice that there was a small threaded hole in the side of distributor, wondered if there should be a grub screw in there?
it couldn't be from manifold gasket or it would run like a sack of spanners, right?

could i have missed an o ring putting stepper motor/distributor back together?

at this stage im out of ideas! and skin on my knuckles! just like a few ideas before i go back in