pulled the other front wheel and original rear wheel apart, ready to build into a new rear.
Found out the rear hub has the normal screw for a freewheel cassette on one side and what i assume to be the screw and lock ring for a fixed wheel on the other side.
The rear hub is in very good condition, due to it being covered in a thick oily gunk, thats protected the chrome, so only a couple small spots of pitting on the center, loads better than the original front one.