The newer, TEMPO chart, refers you to AIP SUP 40/2019 -
https://www.aurora.nats.co.uk/htmlAI...040-en-GB.html
The SUP actually includes the charts and there it says, from the CAA mouth direct OCA(H) for LNAV/VNAV.
But already you knew that.
Neither of which explains what was the reason for VNAV label on the previous version RNAV (GNSS) Z. Checking with the AIP again,
https://www.aurora.nats.co.uk/htmlAI...ics/124009.pdf the CAA called it LNAV/VNAV already there.
Apparently the nice LSY people for some reason changed the
labelling on the original chart, but not on the TEMPO one.
Voila. In LSY graphical language There are 3 different methods how they depict the same minima (my screen is from the LAT chapter, also available to you in FIV under the "Manuals" link from the top-level menu).