Monster 821 battery questions

My Monster 821 not being in regular use as it was, its battery has gone down (11.3V) last time I checked and it is very likely the reason it wouldn’t start.

I do find it strange as I take it for a 30 minute spin every 7-10 days to keep the charge up… and in the past there were times I had not used it for weeks and the bike started ok.

This is what’s happening https://youtu.be/fxfw1AjcCp4

I’m looking at getting this https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/78238
to revive/resurrect the battery.

But not having my own space to store my bike, I will need to remove the battery. I could connect the charger from my house to the bike parked in front but that might annoy the folks walking along the street…

The owners manual does give detailed instructions on removing/installing the battery BUT it also says this is only to be done by Ducati authorised outfit.
https://assets.ctfassets.net/oifkva25gsx4/7qSza9rLTEkN2bfMxtCVmv/544717306c6c134c8abc826979ac9d76/OM_-Monster_821_-EN-MY16.pdf

It would be good to know if from what can be seen in the video whether it is likely a battery issue, if going for the battery optimiser is right approach, and whether me DIY the battery removal is good idea or not.

Your advice would be greatly appreciated.

Cheers,
Brett

The battery has been resurrected by the Optimate charger and is now happily running.