thanks Pleiades for replying so quickly - upon closer inspection the noise is definitely coming from the top of the suspension, where you adjust the preload. Its coming from both sides, not just one.

If I pump the suspension with the bike at stand still (engine off) I can hear what sounds like air escaping the top, when i leave the bike to rest i can hear albeit very faint almost like air bubbles / crackling sound coming from the top, it continues even when the bike has been resting a short while...

it is very faint but definitely there...

any clues? Is it possible air is escaping from here? if so will this have a gradual worsening affect on the suspension?

Maybe im just being paranoid...but thanks again for any advice!