Hi @AndrewJ49,
You have the same name as my old boss 
I’ve rebuilt the JAR against the 3.4.X snapshot and it can be downloaded here: https://github.com/dag81/vesyncOpenhabPyPort/raw/main/manual%20builds/MetOfficeDH-TestOnly-3.4.X/org.openhab.binding.metofficedatahub-3.4.3-SNAPSHOT.jar
Once merged however it will only be available in whatever the current build version is by then so a v4 version, as new bits don’t get back-ported.
If I run on windows it would be to download the jar and copy it into the addon’s sub directory of my installation.Then after restarting the system should see if as a available binding. For openhabian - I’ll have a quick search as there must be a different location. I would imagine it would be to SFTP using WinSCP or an equivalent to the relevant location on where that directory is for openhabian. (It varies for each Linux variant generally).
Will update this once I find the details / or threads about installing addons in openhabian.
It looks like openhabian has a windows share that exposes the relevant directory: Add jar files for binding
You may need to ssh into the unit and chmod the permissions looking at the above thread, if the user it runs under does not have access.