Piaggio B 125?

Hello. I have a 02 plate piaggio beverly 125 (B125) Its 100% standard

I left it for a quite a few weeks without running it. I came back and battery was flat so I charged it. Took a bit to start and It ticks over lovely but when you twist throttle it just dies. As it gets warmer. (I left it warm up for 5 or six mins) it runs better. But not great.
Any help would be fantastic as I could do with bike for work now.. Typical.