Electric shower battery - help?!

[AyeAyeFishyPie]

Apologies for the stupid question.

We have just moved into a house that has a Grohe electric shower. I we t to turn it on and it is flashing 'battery'. But how on earth do you change a battery for that? Am I being dense and the battery is charged by the mains? In which case how do I do that?!

Thanks in advance for any light you can shed!

I'll guess it is a "digital" shower with a remote control. There are a few upmarket makers who like to add complexity.

If you post a photo someone might recognise it.

Otherwise you'll need to track down the Grohe service desk.