I am afraid that as Bourne Grammar is a Controlled school, and so follows the Lincolnshire County Council's Admission Policy which demands only that applicants pass the 11 plus and then allocates places on other criteria, you will not get to know your child's score. The only exception to this is if a child has not reached the pass mark and the parents are considering an appeal.
Those Foundation Schools which allocate places in score order are generally happy to give out the actual scores and sometimes other information about numbers so that parents can gauge their chances of a successful application. This giving of extra information is, I gather, not exactly encouraged by the council as it is not available to those applying to any other type of school.
Unless you have inside knowledge the numbers who have applied and passed for Bourne Grammar and how far away from the school the last person to get in lives will remain unknown until March 1st!
Thanks for the info. Alex. You seem to be very knowledgable on all subjects re. the 11+ ( have seen your input in other areas ) have you been through this before?