TechGnome,

Thanks for your reply, I've quadripple checked it and it's a nvarchar(max)

Code:
Body                   	nvarchar(max),
As a temporary workaround I'm ignoring the changed check if the Body is longer that 4000 characters, not ideal but doesn't seem to be much else that I can do, other than maybe writing a UDF to split the text up into chunks then compare those.