Sorry, I completely forgot to put that kind of info in my post.
I'm using an Arduino Uno Rev2 and am using the WiFiNINA library to connect to wifi and then using the WiFiSSLClient as my client. I've also loaded a cert onto the board for the domain I'm after using the "Firmware Updater" feature of the Arduino IDE but I'm unsure if I need to do more to call(?) it.