Just an update, as a courtesy for all the help.

I still havent had a chance to get to an auto aircon workshop.

I did take another new 2012/13 rex for a spin the other day...

it did exhibit the same noisey clutch and drop in power as I described was bothering me...

but not as loud by about 1/3.

So for the time being, I'll accept its a normal operating noise/function..pending further investigation ....of course...

Though i still maintain it detracts from my..... 'driving pleasure'...