Thanks xcod, I appreciate the tip. However, it would seem this is an extremely proprietary zip file with next to no compatibility. It neither works with 7-Zip, nor Windows 7's native decompression (see second attached screenshot). The author of this zip file should recompress it using a standards compliant zip compressor like 7-Zip, WinZip, or better still Windows.
This decompression error also happens in 7-Zip
Managed to unpack with unar (unarchiver.c3.cx)