Bob the Bimmer

I have a year 2001 e39 BMW 525i saloon. The on/off 'rocker' switch for the heated rear window has gone missing during a valet. This is switch number 14 on the diagram on page 124 of the Owners Handbook, bottom right as you look at the controls for the heating and air conditioning. Any suggestions please on how to find a replacement. BMW main dealers and scrapyards both seem uninterested in my enquiries. Thank you.