Update from my end. Arrived at Cardiff airport last night where my car has been sitting for the last two weeks. Started her up and as usual it fogged up pretty much instantaneously, when I arrived home the Silica Gel bags had arrived, so they where hung on the coat hooks over night (still there). This morning, had to move the car, no fogging, went back out later to change the cabin / pollution filter and again no fogging, Just been out again no that Barbara has arrived and it's sheeting down and again, no fogging, pretty much conclusive they are doing something.
ALSO, as mentioned above changed the Cabin / Pollution filter, took the old one out and could not believe the $hite that came out with it, obviously not been done in a while by the previous owner. New one in which is pretty straightforward and a noticeable difference when Temp is set to low and Air Con gets going, seems to be more powerful and a lot less stuffy in the cabin and NO FOGGING. Ordered a new Cabin Filter for my wife's A4, no issues with her car but we have our cars serviced by a friend of ours and he is pretty old school (only does oily bits) and as mine wasn't changed when I took it there after I purchased my car so I'm pretty sure hers hasn't been either.