Okay, so below is an update:
Took my car in today for the air-con and under-tray to be sorted. Fours hours return drive after setting off at 06:30 this morning to drop the car off.
Mid afternoon I tried to call to obtain an update as did not want to drive up there and find a problem, however could not get through to the dealership via the service desk, too busy apparently.
One hour (half way) into the two hour drive up there and I receive a call telling me they found the problem. They had to drain the gas and the machine used tells them how much gas and how much oil has been extracted. The machine read... no oil, zero, zilch, nothing at all. So that is why it sounded like some firing a Phalax CIWS gun under the bonnet. So definitely not a 'Characteristic' of the car as Mr 'not so smart' put it !. So about turn in the loan car and head home. It's a Vauxhall Mocha, mmm... I could go all Jeremy Clarkson right now but i'll resist
They said they'd raise a case with MG, my worry here is that there may be many people out there putting up with a noisy air-con system which is running with no oil in it at all.If you have this issue, suggest you get it checked.
Long and short... I have told them to fit the new AC pump they ordered, I do not want the old one re-installed and gassed properly as I have no idea what damage has now been done to it with no oil in it and running since April this year. The saga continues