I have solved this. The documentation provided here https://documentation.meraki.com/MX/Client_VPN/AnyConnect_on_the_MX_Appliance/Authentication specifies that a .pem or .cer cert needs to be applied to the concentrator and a child cert needs to be applied to the endpoint. In the above document it has an image of a windows cert store with a cert highlighted, the issue here is that cert needs to have the private key with it. In the image you can see it is not there are only the cert is imported. Once I imported the cert and private key, thankfully I didn't need to me the private key exportable, I had a successful configuration.
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