[Arran]

 I don't want to be a downer but I think I would have passed on it unless I was able to check the picture tube first. These brand Z bugeye sets are somewhat more collectable then the other steel cabinet portables of that era but I still wouldn't risk buying one with a CRT in unknown condition. One thing that seems to be in it's favor is that it is reasonably clean, and all of the knobs and hardware is present, although it looks like the picture tube escutcheon could use a repaint. After you check the CRT, and confirm that it's good, I would put in an order for some replacement pots for those controls, apparently they were very cheaply made and in addition to the tin whisker problems they often get full of crud thanks to the way they are mounted.
Regards
Arran