Just as a follow up - this inspired me to go back and check the seating/TIM on my venom. Took it off, cleaned up and removed the excess. I ended up putting a very minimal amount of TIM on the base of the cooler (filling in the gaps between the heat-pipes), then putting in the two lines of TIM as suggested in the link
As a result, my CPU is running a good 8-10C cooler than before.
Mug happier about the performance now - I was considering ditching it and getting something more 'conventional' like a Megahalems. Looks like I've saved myself best part of £50!
Thought I'd share my experience....
Rich