I received a tip-off and video from a member of the public today of a cockatiel at Brighton Marina, it turned out not to be my missing Luna but someone has obviously lost their pet either way so I went there and tried to catch it. I could hear it calling back to my bird but did not see it at any point. Hopefully this will help someone narrow the search for their own pet. I've checked all the missing sites and couldn't find a report of any birds lost in Brighton or the surrounds. I've got a friend keeping an eye out there for me also and will update if I hear anything.