Chilledpc have reasonable postage charges. unfortunately all those chips mean you need quite alot. If you find it cheaper please share! Never used specialtech before; I'll have a look at them in future.
I didn't have to double-up on the thermal tape in the end. The problem I thought I was facing was really more of an optical illusion.. the stock thermal tape was hanging out the sides of where it makes contact, and simply made it look thicker than it was. I think I could have probably got away with TIM, but it wasn't until I reassembled it that I saw that I was wrong, and I was simply too excited to see if it had worked to bother taking it all apart again. JJ