I'm very happy with the service I get from Andrews & Arnold. Their tech support is on a normal phone number, but is office hours only (email, SMS & IRC support is usually available outside office hours). Their headline prices are a bit higher than some, but you do get a lot of hidden extras - their bandwidth limits are office hours download only, you get an included .co.uk domain, etc.
They're the only ISP I've ever delt with where the boss of the company has phoned ME up to tell me there's a problem and that they're working on it!
AAISP broadband internet