Hi Sue
We've changed the second instance to accept both SQL and Windows logins and the workaround with SQL Logins has fixed the problem. 
Neil

Thanks for your help Sue. Unfortunately one of the instances is set to Windows only logins so I can't use the workaround yet until I talk to the owner. If...

I've run sp_validatelogins on both instances and no logins were returned. There's no local accounts on the server either. I've checked under the instance Security\Logins and I'm listed in both...

Appreciate the help Sue but we're reaching the limits of my knowledge. As far as I can tell, there are no mappings at all. There's only one step on the...

Hi Sue
Thanks for taking an interest. The owner of the job is me and I am a member of the sysadmin group on both instances. There are no specific...