Issue with search function "exact match" not working 1.3.8

Hi all,

We have a large database of car parts which we have created a product selector for. The selector triggers the advanced search function in ZC using the product code as the search term.

This works fine - until - you have two (or more) products which share the same Prefixes, so we have these (just an example):
BO-SP18 - Standard 18" windscreen wiper
BO-SP18S - 18" windscreen wiper with spoiler
BO-SP18FR - Rear 18" windscreen wiper
When the search is run for BO-SP18, although correct, it also brings up the other two which aren't.

The answer, should be, to run an exact match search on "BO-SP18", This is the item code in ZC and I've also, as a test, added it to the product description - still doesn't work returns no results. This is the case when the search term is manually entered in both the basic and advanced searches on ZC.

Our ZC version is 1.3.8a. Hope someone can shed some light for us.
Many thanks

OK, by adding the 'whole word search' add on it will return results in quotes "" as an exact match, but only for title and description, I need it to work on product ID as well.

Would anyone be able to help me as to what code would need to be changed to make this happen?

Thanks