Ok..9 months after leaving Telecom I finally got round to changing ISP's. Changing over was a breeze and (so far) it's definately faster. Hopefully Snap don't go the way of some "other" ISP's that started off well but ended up drowning in a sea of suck!
Edit: One thing that might be useful for customers is having payment options on the invoice and perhaps sending out a direct debit form with the first invoice.