I don't know why I didn't do this sooner. My laptop only really worked on mains power with just enough battery to last an hour or so in sleep mode. This meant if I didn't want to shut down & restart, I would have to keep it plugged in and not forget as my particular laptop doesn't wake up happy from hibernation.
So to the new battery. It is amazing. Almost like new. I say almost as it doesn't seem to have exactly the life that I remember out of my new laptop, but this could be just how I remember it and at that time, I wouldn't have had all the junk that I have on it now. But I can now just close the lid and forget about it until the next time I need it. As I said, I should have done this months ago.