From there website.

Venue normally opens at 8.00am with track runs starting at 10.00am-5pm. It is recommended you arrive before 9:30am to ensure track-time. We can only accept a limited number of sign-ons, so arrive early to avoid disappointment! Normal admission is £10, plus one-off signing on fee of £15 for unlimited runs. This only applies to RWYB Public Track Days.