I don't wish to appear sarcastic but, I'm very surprised that someone with an A1 printer (which are far from common) doesn't have a facility to be able to at least read Publisher files, even if they don't have the software installed.
€dstowe - they have CAD software - I have no idea if CAD they use can read publisher files, but do not think so.
Marko797 - the pdf conversion software I am using is called Primo pdf - and to convert to a pdf you go to file and print, and then choose Primo - it then converts your document into a pdf format. I then get 16 individual pages, which is great if I want to print via my own A4 printer, and then join them all together to make up the A1 poster I require. Might have to go this route if all else fails, but it does look very amatuerish I feel especially as I am going to a show.
Thanks for the pointers though - but looks like my particular problem is not going to be solved very easily.