So here is the deal. Some agents try to reassure sellers that they will check a buyer’s affordability by “financially qualifying” them. The buyers think that’s all they are doing. Looking at your affordability.
What it actually means is they’re going to get their mortgage broker, from whom they get a bonus for referrals, to spend an age on the phone with you, going through your finances and then they will try to appoint themselves as your mortgage broker. Along the way, of course, they will actually check that you can afford the house that you intend to buy. That’s the “financially qualifying” part. That’s the bit they promised to the seller.
This doesn’t mean that you have to get a mortgage through their broker. It means you have to go through the motions to get what you want
Let them do their qualifying thing then politely decline to use their mortgage broker’s offer to get you the mortgage they then recommend for you.
If the EA insist you get a mortgage through their broker, that’s the point in which it becomes illegal, and you can feel free to put a note through the seller’s door saying “I already had a mortgage in place but they are trying to force me to use theirs, AFTER financially qualifying me, which is illegal.”
The seller won’t have a clue what’s going on by the way, because most sellers will read a contract (which they ARE legally bound to) saying “financially qualify” and just assume the EA is gonna engage a credit referencing agency. So the bit about the seller asking them is bending the truth: the seller has asked them by means of signing a contract, without fully understanding what those two specific words mean.
This is becoming increasingly common by the way. If you point blank refuse you may keep coming up against it with other houses. Just play ball then say no once they try to start flogging you stuff.