when I turn the engine off sometimes there is a clunk noise from behind the dash.  It happens usually when the climate control is on Auto rather than Econ.  Could it be the fans or compressor shutting off suddenly ?  Like I say doesn't happen every time and if I restart the car and run it for a minute then turn off there is no clunk.

My wipers do a tiny jiggle on ignition off, only since I upgraded my Ccm. This could be described as a little clunk I guess.

My wipers do a tiny jiggle on ignition off, only since I upgraded my Ccm. This could be described as a little clunk I guess.

 Could be a feature of your upgrade. The owner manual for my 2012 car says "After the windscreen wiper switches off each time or the ignition switches off for the third time, the position of the windscreen wiper changes, this counteracts an early fatigue of the wiper rubbers."

Yey I got another free upgrade pity my wipers are already Naffed

Quite common to get 'Boil-Off' in the air con refrigerant circuit which makes a regular click/clunk/pop sound for several seconds behind the dash...... especially if you are suffering from leakage. Leakage is natural as all metals are porous and the gas (R134A - a Hydro-chloro-flouro-carbon) will find its way through over time but it will take a year or two before you would notice anything significant.... Some garages/service centres will advise you to get your aircon re-gassed every year or two at the most but my opinion of this is don't fix it if it ain't broke......