I need help in rewiring baxi bermuda 552 boiler and firefront?

I need some help. My baxi boiler is not working so I bought a very good second hand one and matching fire front about 4 years old and serviced annually (baxi 552 boiler and baxi 50/5 inset fire) unfortunataly whoever uninstalled the boiler and firefront which I bought just cut off the wire from the boiler and left a very short piece protruding out the small control box with the clear cover on it on the front of the boiler. The other end of the wire is missimg and so is any connector or whatever should be on the is missing end. I think it conncts to the fire front somewhere but I don;t know. I need to get this fixed before I can have the boiler changed. I need a wiring diagram or some sort of illustration please. Your help would be much appreciated.