I just came across this which allows visitors to pay £5 each if booked online 24 hours before the event, or £6 each at the gate, if you turn up at Woburn Safari Park after 3pm this Friday 7th August (tomorrow) for a fundraising event they are holding.
Everything is open the same, you can still go round the drive through zoo bit and see all the animals, and they're holding different fun things such as face painting and bouncy castles for children. The gates are open between 3 and 7:30 with the park closing at 9. I love Woburn Safari, but hate how pricey it can be, so thought I'd pass this on in case anyone wanted to take this up! Sounds like a good evening