Very many thanks for that info Ramesh. I already have an SES 3 switch in my bits 'n pieces box and with those instructions from Engel I should be able to get it all fitted and working. I had heard of DreamArts before but had never seen their website
http://www.dream-arts.de/seiten/aktuell.html until now. There are certainly some interesting bits for the Uboat builders there. Thanks again.
Andrew