@moonstone6
OK, had caffeine now.
i had assumed you had called the bank to ask how much you'd have to pay in ERC, or at the very least calculated that yourself.
you're confusing yourself, or he is misleading you on these figures.
you NEED to ring the bank & ask the outstanding balance & what your current ERC would be.
i think you're seeing the equity as something it's not. It's simply how much (after costs) you get from selling the house & what's left after paying the mortgage off (including the ERC & any other expenses).
so yes you'd get more equity in 18 months (or whatever) because there wouldn't be the ERP. But your mortgage would be lower (as you'll be paying it for the next 18 months)
you need to find out the actual figures, because it may not make that much difference & a lot less hassle to do it now.
you need to work out if you can afford to buy him out & if he'll agree to allow you to port the mortgage solely, you'll still have to prove to the bank you can pay that in your own name, but at least you'll get the benefit if the cheaper rate. But you'll need to be able to show the bank you can afford it at the current rate in 18 months.
GET ALL THE INFORMATION DIRECTLY FROM THE BANK not him!!