Many thanks for the input which has got us over the blockage. A node
with a keyboard/screen/mouse attached will now install automatically
apart from a reboot prompt at the end. A node without
keyboard/screen/mouse appears to install from the network/disk
activity but does not come up at the end. But that is tomorrows task.

Thanks Jan. How to access the errors was big help in telling me what
seemed to be going wrong. Installing http eventually worked but I
think my real problems were with dhcpv6/ipv6 and the server being a
few years old suse flavour of linux with everything disabled.

Thanks Troy. I like "noipv6" which I think may have been the root
problem but I have yet to establish it.

Thanks rader. I am not confident about the DHCP settings but tried
many combinations including the ones you suggest. Now things are
working to some extent we will revisit are options and disable as much
as practicable.

Andy.