The seat switch has started working the mirrors and not the seats on the LSE so I guess after 20 years the ECU battery has decided to empty its contents and added something else to the 'TO DO' list

Replacing with new seems to be a non starter and second hand are rare and still rather pricey for something that comes with little guarantee.

The cheapest solution seems to be a new battery and replacing of the chips that the acid seems to dissolve. Quite a cheap fix if it works.

My father in law is quite handy with a soldering iron and I would be glad for any feed back from anyone that has successfully under taken this repair. An easy fix with 100% success rate or a waste of time that ends in tears and lots of swearing. Thanx for any views.

Battery is easy, cleaning off all the corrosion is not. You may have to remake some tracks and replace a couple of components but as long as the CPU chip is OK it's doable.