Thank you, I'll give that a go.

For reference, all objects are owned by dbo and the account being used has only public, db_datareader, db_datawriter... but what would happen/be the...

Yes, that's right. Both databases are on the same instance and the same server.

How do I do that through Enterprise Manager?

The connection is being made through the use of the ADO.NET Managed Provider for SQL Server, and is using the following connection strings:

dev:

server=Pisang;Trusted_Connection=false;database=eP_Development;User Id=xxxx;Password=xxxx;

live:

server=Pisang;Trusted_Connection=false;database=eP;User Id=xxxx;Password=xxxx;

So apart from the database...

It was useful background info, but I don't think it highlighted the problem in this instance.

The article mentioned the difference between variables that had only been DECLAREd and those that...

Below is one example where this occured. This is the fixed version that actually returns the same results for both databases, but replace all the 'IS NOT NULL' statements...

I've tried running 'sp_dboption', but both databases have the value 'off'.

Thanks for the idea though.

Yes, all the settings on the 'Options' tab of the database 'Properties' dialog box are identical.

ANSI NULL default is turned off... although I should say that I have no...