If space is limited in your engine bay try this stylish expansion tank. 

315mm overall height x 75mm diameter.

850cc capacity.

6mm diameter inlet and overflow unions and two stainless hose clips.

It has a machined, billet aluminium cap with a viton seal, two mounting brackets with rivets and stainless screws.  

POLISHED STAINLESS STEEL EXPANSION TANK #SSEXPAN2