Job done. Excellent write up was of great help (never dared before).
Took about 2 hours (although had a few tea's in between

).
For those who dare not be brave and try it. Just take your time.
Two things I would add :
Don't overtighten the spark plugs.
Use a piece of thick cotton/string to loop over the far air box clip
to help clipping it back on (still needs a push but the string helps lots).
Well happy !!!
