The club has now issued details of how to apply for tickets using special club codes. The dates are 26th, 27th & 28th July 2018.
https://www.porscheclubgb.com/event-discount-and-booking-codes
https://www.silverstoneclassic.com
https://www.porscheclubgb.com/event-discount-and-booking-codes
https://www.silverstoneclassic.com