Thanks Mark for your comments
I am a bit dubious about this exercise that you found worked for you .

I have taken the top off the No 2 K7 and to get to removing the offending key seems to a be a bit advanced for me

However I have blown as much air around the complete offending Key area with high pressure compressed air But unfortunately no change

Sometimes I zero the touch sensitive to 0 and the k7 can be played OK
Unfortunately the initialising of any prerecorded Song the touch sensitive adjust things to initial setting of about 6

Today I checked what 4 shops that sell contact cleaner $14 to $40.
Are you able to tell me what brand of electrical spraying can you used ?. as there seems to be a variety of spray cleaners .

Thanks from Dave L