Cannot Delete Glue record

[Luke Hopkins]

I have a glue (nameserver host) record which hasn't been used in years and I want to delete it (and ultimately re-use the name). Attempting a delete through UKreg (Fasthosts) gives me this:

Error: NameServerHosts Delete (Nameserver deletion failed at registry: 420 Object association prohibits operation.)

I cannot find any way to check what domains are attached to it, and UKreg support are unable to help (check manually was their answer).

We don't have that many domains, so I've checked them all manually, both the zone files and what the registrar has listed as authoritive, but this glue record isn't used by us.

Is there a way/tool which can check what domains are attached to a glue record.

For reference, the name is ns0.broadbean.net

Any advice appreciated.

Thanks
Luke