Well I investigated the throttle linkage problem a little more closely and I didn�t like what I found.
1) When you move the throttle from idle to full speed the engine hunts badly and doesn�t run well at all. I checked the position of the butterfly and when adjusted using this method it is fully open with no choke.
2) When you start the engine and move it from the choke position to full throttle (The position I thought it was running correctly at) the throttle butterfly is slightly closed and running proportionally on choke. I should have noticed this problem earlier as the full throttle running sound was slightly strange but not bad.
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These findings again led me back to the carburettor to retrace my cleaning steps as there is obviously still some sort of restriction. I stand to be correctly if you think otherwise.
I did some more reading and went back to this carburettor picture where item 15 (nozzle) removable however I couldn�t get it out. Could that be the problem?
So it appears when it was running ok it was running proportionally on choke. I should have noticed this earlier.