Intellectual property/patent diligence

I've recently gone under LOI with a company that has a number of patents that are important to its competitive position. I'm wondering if anyone has experience conducting diligence on patents post-LOI and would be able to share best practices on how to manage this part of the process and/or could recommend providers that might make sense to contact for a lower middle market transaction (i.e. will be relatively cost-effective). Thanks in advance for any insights!