Don't worry! Extras including Inner Track, Fast Track, Parking and anything else you may want to enhance your F1 experience next year, are now live to book through your Extras section in your account starting from here:
https://bgp.silverstone.co.uk/account/login
Or from the link below direct on the site:
https://www.silverstone.co.uk/events/formula-1-british-grand-prix/tickets/extras/f1