knock on the door, friendly man in uniform of well known retailer, "hello, we've got an unwanted delivery of a fridge freezer here, need to offload it, going for £50"
(normal price more than 10x that)
uniform, paperwork,ID, even the logo on the van all matches that of well known, high quality, household brand name.
Rang high quality brand, spoke to head office, this is a con, everything is fake, uniform, van, ID, paperwork, everything.
I'm not sure how it works but I'm guessing something along the lines of you agree to have old fridge removed and new fridge installed, first person keeps you chatting and out of the way, maybe doing "paperwork"
second person, (maybe third, but I only saw two) under guise of "removing the old fridge" actually removes anything he likes the look of from your house, including maybe fridge, washing machine, microwave, anything. After all, you've just agreed he can take the fridge, you are not going to worry about a bit of in and out, and hearing sounds of removals, are you?
Don't let them in, call the police, and get registration numbers if you possibly can.