Ann: Notice of Annual General Meeting/Proxy Form, page-9

Without checking, would suggest the constitution requires a member of the BOD to be ratified each AGM, normally by rotation.

"RESOLUTION 3 – ELECTION OF DIRECTOR – MR BEVAN TARRATT
To consider, and if thought fit to pass, the following resolution as an ordinary resolution:

1. “That, for the purpose of clause 11.11 of the Constitution and for all other purposes, Mr Bevan Tarratt, a Director, retires and, being eligible, is-elected as a Director.”"

@Scottmoist also suggest you brush up on the difference between non exec director and exec director.