No Power to AC Compressor on 2006 TDI

Hi there, I'm hoping the brains trust can help me because I don't seem to be able to find anything on the net and the AC Mechanic that I have used (I just went local independent) has less of a clue than me!

I've had the AC Compressor replaced due to the pulley mechanism jamming on the old one. There is now no power at the connector. The AC guy says he has checked the fuse but couldn't find the relay. I will borrow a laptop tomorrow night and run a VCDS scan. Is there something else I can check until then?

The back story is...

The AC (Climate Control- I think it's called Climatronic) was working, but taking a long time to start cooling if the car was hot ie. Left in the sun for a while. If the car was garaged, it would blow cool straight away. From what I have read, this seems to indicate a bad Refrigerant Control Valve (RCV).
Anyway, last week whilst driving (close to home thankfully) I hear a squeal and bang the battery light comes on! Figuring the accessory belt has gone I quickly turn off everything and head back home. The verdict was a fried belt due to the AC Pulley mechanism failing and seizing.
I manage to source a low km's used compressor from a reputable dismantler, unseize the pulley, get a new belt on and drive down to said AC guy. He fits the Compressor, gasses up the system and rings to say it's not working! He assures me it will be the RCV so I begrudgingly agree to a new one (for $175!!). I wait all day, then ring at 4pm to get the news that it still won't pump and wait for it... He's just discovered there's no power to the Compressor! Far out, I'm an amateur mechanic and even I know the first thing to check for is power. Especially before throwing a $175 sensor at it!!

So you can see why I have no faith left in this mechanic. Any suggestions would be greatly appreciated.