A little update.
I see an orange shoulder tang a couple of weeks back for sale from a tank that was being broken down so went to view it and tonight I picked it up and is a lovely healthy fish as well as an urchin.
It has settled in well and there has been no real aggression from any of the other tangs. I has muched on pellet and frozen so seems happy enough.
It was in a 3ft tank so I'm sure it will be happy of the extra swimming space and the brother inlaw will move it upto his 8x3x2 should it get to big for mine so it has a good home secured for it even if it does outgrow my 6ft