Brennan is a relatively common surname in the area. Another possibility might be Burman. Or it could be neither of these. Would it be better to enter Brennan as an educated guess or to simply enter B* ?
Look at all the other handwriting in your batch to see what similarities you find in the letters and it always helps to post the batch code [XXXX-111] so we can see more of what you see
Always best to share the batch! But, if you are going to use wildcards, you should at least include the letters you are certain of - like, B*an