air/con hydraulic fan issue

[love my commander]

I am in UK with a 3ltr diesel commander

Hope someone can help me with problem that may be the hydraulic fan or a control module to it.

I do not have any problems with engine cooling, no overheating and the temp gauge is rock solid in middle of gauge ( so assume it spins up as needed)
I do not have any problems with transmission cooling, No message on information centre saying transmission overheat ( so assume spins up as needed)
This to me indicates that the solenoid valve is operating for those two conditions
The fan spins at tickover as stated between 100 to 500 rpm
With engine off the fan can be spun by hand with a gentle push
Six weeks ago towed caravan over 100 miles and had no overheat problems with engine or transmission

However it does not spin up when the air/con is calling either in auto or manual mode

the air con system has recently been re charged by a reputable company and it was there diagnosis that the fan should be spinning faster than the 100 to 500 at tickover
when air con calling indicated by compressor running in order to clear the heat off the evaporator.
There gauges showed a causing high pressure in the regfrigerant due to inadqueate cooling over the evaporator causing poor cabin cooling. only drops ambient air by 3 to 4 degrees at most e.g. outside 23 degrees C air off vent 18 to 19 degrees C

When travelling the air con does cool better supporting that diagnosis since the air movement of the vehicle is giving extra evaporator cooling allowing the pressure to come down.

There are no DTC's flashing up

I understand that if a sensor goes faulty the fan defaults to 100% full speed, if so it does not look like a sensor is faulty.

a) Would the air con system being low ( it had approx 50% charge left in system) trigger a DTC to inhibit the fan running and its this that now needs resetting?

b) Can I jumper a 12v supply to the solenoid to force it to full open and thus test if fan goes to 100% full speed?
If so which connection would I put the 12v supply to? pin number and/or wire colour please.

If I can prove it is the solenoid not working I have identfied the part number and can change it myself, assuming we can get the part in the UK.
If it is the fan itself again not beyond changing it myself
If it is anything else then prob have to resort to dealer and a kind bank manager

I have obtained the TSB 07-002-06 which gives a check aid chart to check such as resistance reading for the solenoid.
It also gives a current range if it is working providing I can jumper the connections.

Any help would be most appreciated

[ima poster]

My fan runs at a speed when idling (no idea how many rpm, but it is not especially fast). Turning the aircon on full alters the engine note, but the fan speed doesn't change.

[cav.turbo]

I have 3.0crd like you and my air con does not seem to do anything. I haven't had it recharged yet. (who did you use and what did it cost)

My fans the same and just seems to sit at a steady speed with air con on or off.