Newbie, Vo2 max not updating for cycling (fenix 6x)

Hi all took delivery of my 6x last week and so far im chuffed with it but one thing that's annoying is the V02 max.

After messing with settings last week I managed to get it to work and after a short walk on Friday it gave me my estimate.. Today (31st Jan) I cycled 26 miles and pushed hard as I could and when I ended it I was hoping for some update but my V02 max still says Friday 29th.

My mates says it only updates when it sees an improvement, but I find it hard to believe that it's made its assumption after a short walk and there's no adjustment after a 26 mile cycle. 

Does anyone know any of settings to check please to ensure its enabled for cycling.

Thanks in advance guys Thumbsup