I could not leave this as was....
So earlier this week I decided to send the General Manager at Brooklands a letter, setting out my disappointment regarding this problem, and to tell them I would no longer be using their services again.
What happened next was a total surprise, the very next day, I received a call from The Customer Services Manager at Brooklands, who had been asked to call me following my letter, but was already preparing to contact me, as he has been reading this thread !!!
Following a 20 minute phone call, and with the records for the previous rust repair have now been located.

My warranty claim has been authorised, and my car is booked in to be repaired in the next couple of weeks.
The Customer Service Manager could have not been more apologetic, and had accepted, they had made mistakes.
To me this issue had become much more than who was going to pay for the repair, but actually how I was being treat by the dealer, I hope they have learnt from this.
One thing I have learnt is that the dealers, check on forums and read our comments, and are taking note.