Hi
From what you are saying yes it does sound like a bad battery
It’s not the hardest thing to replace but it can be a challenge for some
Here’s a video guide for replacing the battery
[link|https://m.youtube.com/watch?v=SBeHaqnw45w|https://m.youtube.com/watch?v=SBeHaqnw45w|new_window=true]
Here’s a link to a part as well
https://www.ebay.co.uk/itm/363815563351?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=2OtC5OAAQh6&sssrc=2349624&ssuid=0ACG7idPSQ6&var=&widget_ver=artemis&media=COPY
Hopefully this helps
Any questions please ask
Thanks:-)