Thanks for the reply, I have tried all the operations you mentioned including changing the float plastic needle and housing, (the cap which includes the rubber fuel primer). When the spark plug and above parts were first replaced it started first time but as been progessively harder to start. The plug remains dry even after several primings and pulls with the starter. I've tried putting a small quantity of fuel directly into the combustion chamber and this did work eventually.
I took the cap off the carb, the one which retains the springs and the innards look as if they could do with a clean, hence the request for help with removing it via pdf service repair pages.
It appears to be a problem with fuel not reaching the chamber does this seem a likely answer to you.
Regards, Bob
