I have been doing a bit more digging. According to Belarc Advisor I have two versions of Office installed on my laptop- versions 16 & 18. Version 16 appears to encompass Office 2016, 2019 & 2021 but I can't find a reference for V.18.

Looking at the applications installed on the laptop in the "Uninstall or change a program" screen it tells me I only have Microsoft-365 installed, so I'm a bit perplexed (to say the least)