I'm pricing up radiators right now - and there is a very good deal on
" radiator packs" in the Stelrad Softline range.

Bascially you choose whatever you want up to a "total btu" figure

Downside is maximum length of any rad (in this deal) is 1200mm, and in
some locations I need something a good bit bigger.

So - how practical is it to run two rads in series - i.e. straight
horizontal copper pipe out of the first and into the second, with trv
and lockshield at the respective further ends?

I figure it would only cost me two threaded male compression fittings
(and bit of pipe) to jump between the two rads- and have the two
function as one.

Any pitfalls here?