Changes since SOA version
IXFR is a zone transfer request that returns changes since a specific SOA version. Enter the SOA version to request changes since then.
Not an apex domain
The domain ns-1872.awsdns-42.co.uk is not the root of its zone.
Instead, try zone transfer on awsdns-42.co.uk .
Instead, try zone transfer on awsdns-42.co.uk .