Was prompted to post this having seen post for lifetime membership.
Normal joint adult annual memberhsip is £105 but if one of you is 60+ you can contact them and get a 25% reduction to £78. It would be helpful if they advised members, or automatically reduced your membership fee, but no, you have to contact them to set it up.
Individual Senior Membership is £47.50 as opposed to £63 adult membership.
You need to have been a member for five of the previous ten yrs to qualify.
Prior to this I always let our membership lapse, waited a couple of months and then applied as a new member in the name of my husband if I'd last been first named and vice versa. As is often the case new membership rates are lower than existing members. This didn't preclude our qualifying for the senior rate as between us we'd been members for five of the prev ten years.