EAP-TLS / ACS / Specifying which cert to use

Hi all I’ve an issue that I’m struggling to type into google, hoping someone could steer me in the right direction. We’ve setup EAP-TLS… ACS 5.5. Access policy is using multiple ID stores. Computer authentication.
When connecting to the wifi network, I get a “terminate / Connect” warning about the certificate being valid, but its Authority is not configured as a valid trust anchor on this profile. Clicking connect lets me get a connection. Upon looking at the details, it reveals it’s using certificate EDU1… which it shouldn’t be. The correct certificate is installed on ACS, the corresponding certificate is on the laptop, but I can’t figure out which part of ACS dictates which certificate it will use for this connection. I’m trawling through menus, obviously missing it. I am literally looking for a field with a path to the cert, or a drop down menu I’m sure, I just can not find it!
Any ideas would be much appreciated. I’m fairly new to this setup, fairly new to networking in general but tried to give the details above – hope they’re relevant. I reckon part of my issue is I’m not comfortable with it yet so don’t know how to properly ask for advice on it. Hopefully at least some of it makes sense! Thanks very much John