On 22 Oct, 14:10, Bill wrote:
Thanks folks. I've not read anything particularly bad about them yet,
so veering towards buying them.

I have bought some. The bleed plugs are very weak and inaccesible on
double rads. They are in the form of a small brass crew in plug with a
square section for the bleed key to fit over. Because they are so
small they are weak and one has broken off whilst looseneing to bleed
- now faced with drilling and tapping a replacement (it is on a double
radiator and no space to get a drill in to drill it out. So be careful
when tightening/loosening.