Well, you learn something everyday.. I didn't know that Piquerez developed the Super Compressor case until I bought this 70's Seascoper.

Here is the condensed story:
"In the same year that the first Rolex Submariner and Blancpain Fifty Fathoms were introduced, a renowned watch case manufacturer in the Bernese Jura, Switzerland, by the name of Ervin Piquerez S.A. (EPSA), patented a case sealing method that utilized the water pressure that a diver’s watch is exposed to at depth. By taking advantage of pressure to compress the case back against the O-ring seal, the Piquerez design provided superior sealing of the case, the deeper the dive. They were known as the Super Compressors"

More info here: http://scubawatch.org/EPSA_SC_FAQ.html

This is a Felca Seascoper from around 1970. It has circled SAP emblem on the dial, the most promising suggestion so far is that it could be South African Police Diving Unit, which was around in the late 60's/early 70's. The font type is certainly similar to the non-shield examples I've seen online. Any other info would be appreciated though.

I've posted some info about Felca's history and specs etc on my blog, with some more pics..
http://heuerville.wordpress.com/2012/09/22/felca-seascoper-super-compressor/

Cheers
Stewart