Thanks for your quick response, you're right it is also useful to know which branch of Rainbows are not the right ones, although Bedfordshire would be nice as it is where I am now living! In fact I came across a Rainbow in Meppershall cemetary with a link to Highgate London, do you want me to pass on the MI?

I will try and look at the Goldsmiths' archives too, I hadn't realised gold and silver smiths would have been covered by the same company.

Good luck with your research
Theresa