cloudbase being calculated but not charted

[glenosAU]

This is possibly a weewx issue and my lack of understanding. NeoWX is displaying a card for cloudbase and a chart box, however the chart is blank just the x and y axis are show, x-axis is 0-5m and y-axis all points are Thu 01 11:00.

Looking in the sqlite DB, cloudbase is stored in archive_day_cloudbase with 8 records present the first is 8 days ago at midnight. I assume these are being calculated using the daily data. There is not a column for cloudbase in the Archive table, do I need to add a column?

I have a similar ET question but it is definitely a WeeWx question.