Great days out/Wookey Hole

Hi, just joined the club and received the welcome pack, and seen the great days out booklet, we are planning a trip down to Bristol area in afew weeks and noticed the offer for wookey hole. Has anyone been there with the voucher and can confirm if the price for 2 adults and 2 kids will be just £32 ie kids are both free or if only 1 will be free, as it just states "Buy one full price ticket and get the cheapest free" or would I need to use 2 vouchers.

Any help would be greatly appreciated.

Thank you