sized tyres. So had a hunt around on the interweb thingee, and with the help of someone who had seen a thread on 5 stud options before, I came up with this setup.
Swivel housing with excess radius ground off ready for building up.
Bits of flat plate I welded together and then ground down to fit top of swivel housing
Plate sitting in place ready to be welded on.
Plates have been welded onto swivel housing. Extra 12 mm plate has also been welded to the cast steel steering arms. Drilling hole right through all the extra steel bits, (about 30mm thick in all).
And the other side (just to shut Chopper up
) Note the CTR branding 
The idea was to drill through all steel at the same time to line up all holes, and then tap out the swivel housing with a 12mm thread so I could wind a cap screw in through the inner side of the swivel, and put and extra cone washer and nut on the 5th stud. Unfortunately the cap crews didn't come threaded all the way to the head.
So I had them cut all the way to the head so i could wind them fully home.
Finished deal looks okay, and will hopefully cure the loose swivel housing stud issues i have been having, (note: both 5th studs have nylock nuts on them now as well)
The arms that I have used are off an old 60 series housing, but they are temporary. I will grab a set of TG high steer arms (when they arrive) and adapt them to the 5 stud setup.