I don't think it's a railcard - just a special offer. And it's composite you - if you are old enough - can take advantage of both at the same time:
It’s time to discover the world again, and there’s no better way to make some new unforgettable memories than with our new Senior Savers Club, exclusively for those age 60 and over. Designed to help you get out there and really enjoy all life has to offer, travelling with confidence – to everything from weekends away by the coast to a day out in the city with the grandchildren. Book from 20 September for travel from 18 to 31 October to save more than 30% on train tickets – and save an additional third when you use your Senior Railcard!
I'm not sure if the discounts are added together or taken one after the other - whether a fare of (say) £40 reduced to £26.40 and then to £18.50, or if there's a 64% reduction applied, giving a fare of £14.40.