All my CDROMs are 700Mbyte and the ISO is 722Mbyte - the writer refuses to squeeze the image onto the disk. The writer also refuses to put the image onto a DVD, insisting it is for CDRs only. I suspect the latter is something I can override, which I will look into. Unless there are DVD images somewhere that I am missing? Otherwise I'll have to order some 750Mbyte oversized CDRs and burn to one of those.
I've reconfigured the router and network, so there is no urgent need for the server to be up and running, so I can afford a few days to get it fixed.