Humbrol acrylic paint questions

[Edward Pinniger]

Has anyone had any experience with using the new Humbrol/Airfix acrylic paints? (released earlier this year). I've seen them for sale online and they seem to have a very good range of colours, particularly shades of grey.

Also, are there any hobby shops in the Berkshire/south Buckinghamshire and Oxfordshire/Surrey area (UK) which stock these paints? I haven't found any so far - most don't even stock Revell or Tamiya acrylics.
There are plenty of online stores with Humbrol acrylics, but I'd rather buy them from a hobby shop if possible...