On 23/11/2019 07:50, Harry Bloomfield wrote:
newshound presented the following explanation :
IMHO they are designed to be difficult to DIY (e.g. for replacing
batteries).

The batteries are extremely easy to replace - a couple of fixings
retaining a plastic cover, then just disconnect and pull them out.

Wasn't at all obvious on my model. I only figured out how to do it when
I needed to take it off the rail, which involved a lot of grovelling
around on the floor, and even then it was not particularly easy.