Thanks for the input jokky, but the issue is that whenever the campaign is cloned the only way to assign the correct email templates to campaign emails is to do it directly in the database.
This is for an application that is running 31 websites - 1 master domain and 32 sub-domains - and generally speaking when a new campaign is created on the master site it will need to be mirrored on all of the sub-domains.
I'm going to develop a custom gui for the client to be able to use to do this. That way I can run my own procedure(s) to correct the template id for all the cloned campaign emails.