Thanks, but I don't really know how to tell the difference between installers, tbh. I've looked for local firms who are NSI or SSAIB approved, and other than checking their website, looking for reviews and questioning the guy who comes to quote, I'm not really sure what I can do.
I've liked most of them, they've spec'd it the same, been clear in their answers and provided quotes with breakdowns. Which has led me back to kit... Also, I'd rather get the opinions of people who've actually installed/used these things rather than trust my own instincts... )