Jon asked:
Has it prompted your for the IP of the nameserver? If
not then maybe
it's an issue with the 123-Reg Control Panel?
Yes, and I keep telling it the correct one!
Quote from 123-Reg control panel (in my case using
bitfolk as secondaries)
When entering the IP address for a nameserver within
example1.co.uk, you
will need to use an IP address which has not been used as a nameserver
for a different domain. You cannot use the same IP for different
nameservers.
This is the paragraph I do not believe, because it has never been an
issue with any of the domains I have registered with them.
Alternatively, there might be workarounds e.g. listing
a slightly
different dns name in the short-term e.g. sub1 or top1 in both DNS and
delegation and changing it back a bit later.
This is what I am going to try next.
Ian