Hey man sorry me again- did exactly as you said and there was a bubbling sound, so i left the caps off, revved it a few times over about ten mins, lots of bubbles came out so kept going until there was minimal
Bubbles then replaced rad cap. Topped up along the way, revved again, still bubbles and some
Out of the expansion tank, tried revving few more times until it looked like no more bubbles but there is still a bubbly sound!
By this time the temp was up to normal, held the revs for a bit, temp rised slightly, took off the revs temp went down slightly (like 1mm ish on the gauge not accurate i know) then rolled up a leaflet and stuck it in the viscous fan, stopped really easy and I was able to roll it back (started rotating pretty much straightaway again)
Any ideas? Getting a bit desperate now with it being xmas! Only overheats on the motorway but where I am there isnt a good run where i'd have chance to get off if it overheats again
Thanks mate and sorry to come back with more issues!