English Heritage Adult Membership for Two - Key InfoVoucher Validation Your voucher is valid until 01 Jul 20 You must validate book and use your voucher within the voucher expiry date.Duration: Your membership will last one year from point of redemption.Group Size: This membership is valid for two adults and up to six children under 18 within your family group.Weather Dependent: NoThe minimum age for an adult membership is 18 years old.Availability: Your membership will be delivered Monday to Saturday Delivery will be within 21 days of redemption.