Thank you Gerry, I've seen this website before, but had forgotten about it.
They do that paint in 40ml jars, but even that is nearly 3 times the size you get Humbrol in.
They also do "Acrylic Enamel" which just doesn't sound right to me.
There is a store locator button towards the bottom of their menu... there are 3 or 4 shops near me that stock it, so I may take a look.
My Mum calls me Steve.
1:32 on 16·5mm track. Gnot strictly minimum gauge... but it is the minimum that I'm working with !
And now... a critter in 1/24th... from scratch!