Follow up ....
Engine hasn't been started for nearly 2 weeks --- I ran the carb dry after the last use.
Today .... connected a strobe and it flashed on 1st pull so there was something going on at the plugs so disconnected it.
Yes there is a stiff link wire that moves under the flywheel when the choke is pulled.
The choke knob has "slow" "fast" and "start" printed on it but I have never rotated this only pulled it out to choke.
Today I rotated it and depending where it is in rotation how much the stiff wire travels when pulled to choke.
In the "start" position -- fully clockwise --- and choked the motor would not start so I took the plugs out --- they were wet when shaken onto my hand.
I replaced both plugs but it took about 10 pulls before the motor spluttered into life ---- once it is started and stopped the slightest of pulls will get it running again.
I had to rotate the knob anti clockwise (choke off) to keep the motor idling
At no time did it kick back.
Used for about 2 hours of stop /start fishing with no problem .
The boat will be off the water soon and in my garden where I can look more into it , clean the carb ,filter ,etc and do some more head scratching.
Many thanks for your time.....