If anyone is missing the original T Gel since it was discontinued I'd recommend trying Capasal, I've actually found it better for my scalp psoriasis!
Superdrug seem to be the only place you can buy it and it isn't in-store but can be delivered or.click & collect
www.superdrug.com/hair/hair-treatments/medicated-hair-treatments/capasal-therapeutic-shampoo-250ml/p/947458