This was an excellent addition to the thread, thank you!
I ran the steps as described and when the system checked the existing certificate it threw up this error:
The current certificate does not match the network configuration and it might not work with TLS.
So I selected the menu option to generate a new certificate, exported it and imported the new cert into my Reports application. Unfortunatly this did not resolve the problem for me, in fact I started getting new memory exception errors (I took screenshots and am forwarding them to my SolarWinds support ticket). Attempting to run a report with or without TLS enabled has the same errors as before, followed by a new memory exception error.
So thanks for the information, I think it did identify something we hadn't considered before, but I'm still back to where I was.