Bottle cage for Brompton folding bikes

I've been frustrated with the bottle cage offerings for the Brompton for a while. Nothing really did everything I wanted. I don't use the bike for commuting (not very often anyway), it's mainly used for throwing in the back of the car and taken on days out, weekends away etc. I was previously using an SKS bottle cage that velcro'd on, but I had to remove it every time I folded the bike or else I couldn't lay the bike on its side in the car since it stuck out from the side.

I tried a Monkii ca