My sadly long-gone Wilesco was the simple one with the single acting
oscillating cylinder. However the safety valve and whistle on the one in
the photo appear the same as I remember on mine. I'm not sure what you
mean when you say they fell off. They screw into separate openings on the
boiler (which IIRC was brass and either nickel or chrome plated.) Perhaps
you've just lost them? If you cannot find them just order from the maker:

http://www.wilesco.de/wilesco/us/index.html