How can I stop water constantly dripping from my Mira Sport electric shower head(s) when it's turned off.

Margaret Silsby, February 2017

You'll probably need to replace the shutoff valve.

Its strange you missed this result when you did your search to help yourself before posting here:

https://www.mirashowers.co.uk/support/fault-diagnosis/

Spares here:

https://www.showerdoc.com/shower-spares/mira (That site is well worth bookmarking. Also note: changing a flow valve is relatively straightforward but can be a bit of a pig sometimes)

xxx, February 2017