Hi Paul,
Can you also confirm whether the gauge is actually 5", not 5.5"?
Finally, do you know whether the boiler is serviceable? It looks from your pic into the smokebox that there are 2 tubes/flues missing, suggesting none of the tubes are expanded in to the steel boiler.
Steel boilers are unfortunately not very well accepted in the UK, as they always corrode, however slowly (and a copper boiler well cared for does not), and the testing regime is more stringent. Other parts of the world are much more accepting of them, like Europe.
Good luck and I hope it finds a good home!
Edited By JasonB on 20/06/2013 16:17:43