Any advice on what expansion bottle is widely used ?
Want to mount it in the same position as the Caterham on the top rail behind the rad.
Any photos would be appreciated.

Get one from Caterham here

Heres some pics of what i did with a bit of ali to mount my K series bottle from a rover. Mine is designed to fit on the vertical bulkhead/scuttle part though.
Rescued attachment K series bottle small.jpg

Bracket
Rescued attachment K series bracket small.jpg

And the back
Rescued attachment K series bottle rear small.jpg

I used a Rover one as well. Made an ali bracket and mounted it on the scuttle shelf

Though if you try and find a second hand one you'll have to clean out the mayo first

Really best to mount the bottle on the bulkhead, this gives it the shortest run from the continuous bleeder on the inlet manifold.


The Rover bottle is the Rover 25 (and bubble shape 200) bottle the 45/400 bottle is very different.

Round Caterham bottle is VW or Astra -- a Valeo part.