In regards nchar and nvarchar, its purely down to the 3rd party design for this.

There's a lot of this throughout their table designs, however they have very little willingness to...

Thanks for that advice & info.

I've checked our db server this morning and the results for the HEAP query have come back as '0' for both columns.

However, there was a...

Data Types:

a.client = nvarchar(25), not null

a.status = nvarchar(1), not null

a.attribute_id = nvarchar(4), not null

SQL 2012 Standard Edition original SQL Instance

Migration of the SQL is to a new instance on the same VM Server.

The migration was due to application upgrades requiring this, not DB...