Have you asked Peter Emanuel of Asahi Photo (AKA Pentax Camera Repairs)
service@asahiphoto.co.uk. He's just dispatched my LX and MX back to me. Claims the metering on my LX is now better than on his!
I have heard that the Electro Spotmatic and ES had slightly fragile electronics, and got a comment on twitter. In this tweet:
View: https://BANNED/BustertheLegend/status/1534470873901588481
Gav Gordon is referring to the Pentax ES and Electro Spotmatic, so you could try contacting him. However I suspect his repairers are in the US.
According to
https://www.pentaxforums.com/camerareviews/pentax-es.html it was the Electro that had serious electronics issues and they were mostly sorted by the ES. If it was effectively a reliable Electro, it could be an excellent camera. All my New Zealand, Tasmania and Northern Territory Kodachromes were photoed with the Electro and there were very few exposure issues!