My 2016 Bosch Intuvia controller has stopped switching on, - the only way to get it working currently is by using the charging light switch on the main battery, and then the bike works fine, but it is not very convenient The internal battery is dead. I looked at a video on Youtube on how to replace the internal battery but this needs soldering skills and courage I don't have. Can anyone recommend a source that I could mail the controller to who could replace the internal battery at a reasonable cost, and mail it back to me. The bike is a Raleigh Captus, and I am in the Bristol area.