I've not seen these before but they don't look like your typical lock shield valve, can you isolate these to remove a radiator ? the opposite side as the manual TRV
http://img.photobucket.com/albums/v136/cpuspec/Mobile Uploads/IMG_20150130_094112.jpg
http://img.photobucket.com/albums/v136/cpuspec/Mobile Uploads/IMG_20150130_094112.jpg