Thor, or should that be Zeus?

[Chaz]

Something like this (With fans stuck on it) would work well

http://www.ebay.co.uk/itm/Baxi-105HE...UAAOSwA3dYPbSU

Simply splice the radiator into the return.

Thanks. Certainly an option.

I like this too, not sure how adequate it would be on a 4KW Spindle.

https://www.youtube.com/watch?v=2OZCviK0msg