I pulled the rifle apart and polished all the contact points, I noticed on the cocking piece a small depression where the sear had made contact when cocking the weapon ( maybe heavy handed slamming the bolt forward could have caused this, who knows). Anyhow I maintained the angle and polished it out and it seems to have cured it. My trigger is constitantly smooth in operation now, thanks for the advice Peter. One thing I did notice was the lack off the spacer the sits under the forward trigger guard, I only have a lock washer beneath it.