Cooling system pressurization tool

Which UK DIY shop(s) would sell me the cooling pressuration tool compatible with the Exige? I gotta buy one and ship it - American offerings not compatible with the tank cap’s thread or diameter (yet it looks fairly standard to me).

It’s actually a brake system bleeder kit that uses the tyre pressure to pressurize the system (whether it’s brakes or coolant. I think EZ bleed or something.
It turns out that the Rover cooling tank cap is the same as most brake reservoir caps…

I have one at home, could check it out tonight and see what it says on the bottle (sorry, box long time gone)