>For the table in question....are there indexes and/or relation/constraints involved, and/or any delete triggers?

Index on that field is enabled, no relation, constraint or trigger involved.

>Also, have you looked at the execution plan?

I have attached an image of the result to this message. The second image shows the details for the 97%.

>There are different possible optoins....if the table has an ID you can use (for the IDs to be deleted), if you're passing them in the same order as the original table (if you're using a clustered index), you may get more cache hits.

I think using a date field might be an issue. I might be better to find the primary key first and delete everything older than that primary key.