I'm not really feeling masochistic enough to disentangle their previous bills, and they are somewhat hazy about what tariff or offer they are / were on. True confusion pricing at work!
Going through the 'existing customer' product upgrade process on BT.com doesn't result in a better deal being offered - do you have to call up the customer options / retentions team to get this?
I was just thinking they could start afresh with a different ISP, question is did they tie themselves into a new 12-month contract when they used the BT 'Home Move' service? (They had a BT service at the old address.) The emails they received from BT about the home move don't mention anything.
Unless I'm much mistaken there's no easy way to find out whether you are still in contract with BT!
If they go to their account on the BT web site they'll be able to download their bills month by month and see exactly what they are paying
Their bill will no doubt be increasing in January 2018 and they will have 30 days from the receipt of the email advising them of the new prices to either say they want to move to a new ISP or haggle for a better price
Any change to a BT broadband contract is likely to start a new 12 or 18 month contract