As Jon says, I replaced my Plus 8 one (after 11 years) and it's accessible from the top if you are reasonably agile, I'm 74..
I replaced like for like @ 11 years it owed me nothing and never saw a battery charger but I use it throughout the year.
The radio memory will go as will the temporary fine mixture adjustments for the ECU but a few miles down the road and it will relearn.r
![[Linked Image]](https://www.tm-img.com/images/2025/10/18/5B742476-44B6-4B2F-9068-5016CB1D0A50.jpeg)
This was mine 68 quid delivered.