GMDS - It's the new name for GAMCO, long established overhaul centre in Abu Dhabi. They were created with Gulf Air but since Abu Dhabi pulled out of Gulf Air ownership and created Etihad, GAMCO now look after Etihad and decided to changed their name a week or two ago.
As they have no affiliation with Gulf Air anymore the rebranding makes sense although GAMCO was a well known name in the industry.