I have never bought a MFD, but I know several people who have, and they seem significantly less reliable than separate devices. All but one of them (75%) are on their second MFD (that's one each of Canon, Lexmark and HP) - I've had my separate Canon scanner and inkjet longer than any of them, without problems.
There's a great deal of convenience (and space saved) with MFDs. but at a cost premium, as you have discovered.
Perhaps, at that price, it is worth repairing.
It might be something simple, but going to the manfr., you'll probably shell out £50 to be told either that it's not possible, or the repair would cost more than a replacement.
If you happen to know of a local PC / printer specialist (NOT PC world!!) that will take a look on a no-fix-no fee basis you might be in luck.
SD