Shops for adult practice wear? (UK)

Basically just the title! Does anyone know some good online stores (or physical ones, I’m in Sheffield) for adult practice wear (over boot leggings, jackets etc) in the UK? I’m currently wearing basic black Decathlon leggings with stirrups but would like some fun ones too!One concern – I’m not a ‘small’ girl, I’m 5’9 tall and a size 14-16, so plus size options would be great please!