ow75 wrote: I don't really know what I'm looking for regarding spark plug colour so any advice would be gratefull,am I right in assuming this will indicate which piston I have a problem with if it is a rings fault?
Correct
as long as the plugs have a couple of hundred miles on them, look for the following.
White looking tip = engine running too lean
A colour like a cup of tea = correct setting
Soft black sooty deposits that come off on your fingers = engine running too rich ( see note below )
Hard black sooty deposits and a general claggy look on 1 or more = engine burning oil ( not good

)
Note = Rich running is caused by :-
A blocked or wet air filter.
The choke is stuck on.
Another fault in the Carb (less likely)
.