T120 2016 Charging/starting Fault

Hi all.
I have had a strange electrical fault on my 2016 T120 Bonneville, which hopefully someone can help me with.
I took it for it's last ride of the year in December, just a short run of 15 miles and it started instantly as normal, but soon I noticed the odometer wasn't clocking the miles. It was a bit nippy so I tried to switch on the heated grips only to get an abridged warning message on the speedo of low battery. Thinking that the battery was just a bit low, after the bike had been stood a few weeks unused, I just carried on. Having been at my destination for a couple of hours, I then tried to start the bike only to get the dreaded solenoid click. Luckily there was a nearby slope so I just bumped it and got the engine running. As I rode home I noticed that the odometer had started working again as did the heated grips.
It's now been stood untouched for at least 6 weeks and again it starts instantly on the button. I was thinking that it may just need a new battery, but everything is working as it should, even the charging rate, so I'm a bit stumped as to what it could be.

 

Thanks for the replies. I've had the bike from new and it's on its original battery. The battery connections are tight and it's charging around 14V with a multimeter. Could it be an ECU issue or even an intermittent fault with the battery? I would have thought the battery would be due changing, but all the lights are bright without the engine running and it starts instantly even after being stood.

 

12.3V with the ignition off, drops to 12V with ignition and lights on.

 

You're probably right. I'll just get a new battery anyway due to it's age and take it from there. It's just puzzling how it starts without hesitation, but I don't want to be let down again in the future, as they're not the easiest thing to bump start without a gradient.