I have had a look in /etc/aliases but there is no mention of this forward. It also only seems to contain the system names (ie postmaster, root, nobody, www etc).
I have managed to find the kathlene, if I look in the Netinfo Manager under afpuser_aliases, but it doesnt appear to be linked to anything else, and if I look in the users under Netinfo Manager Kate Mchugh (the correct name) only has the aliases k.mchugh (the address that forwards), katemchugh and kmchugh (neither of which forward)