Anyone got a spare brake fluid reservoir cap?
 

I'm going to be bleeding my brakes at the weekend and have bought a Gunson's Eezibleed thing to make the job easier.
It works by pressurizing the fluid reservoir to push the old fluid out when you open the bleed nipple.
However none of the supplied caps fit the Scoob reservoir (there's a surprise!) so I'm going to have to modify a Subaru cap by drilling a 10mm hole in it.
Just to be on the safe side I would like a spare in case it all goes 'Pete Tong' on me.
Can anyone help?