Well, I replaced the tappets and stem seals, both with brand new parts.
Started it up, tappets were clicking - then stopped almost instantly, AWESOME!
At least I thought it was. I decided to go for a drive after a days messing in freezing cold I'd go take advantage. I brought the car up to temp. drove it for about 10 minutes, then the tapping started again, it continued to do it for the next 30 mins, regardless of where the revs sat, so I have got seriously fed up and come home
F**king stupid heap, well annoyed.
Which brings me back to my original question, is it possible I've got low oil pressure in the head?!?!