Spirea X were formed by Jim Beattie who had left Primal Scream, having founded the band with Bobby Gillespie, after their first album. This band tapped into a certain part of the British musical zeitgeist with elements of stuff like Jesus and Mary Chain, Stone Roses, Ride and perhaps Cocteau Twins.
Named after a Primal Scream b-side, they released a couple of singles and an album on 4AD, but were quite short lived.
Youtube backup link
Is she a dedicated backup singer? That’s not something you see often. Lead singer, sure, but backup singer in a small band like this, with just one backup as opposed to a trio or so? Never seen it.
I didn’t pay a lot of attention to Spirea X, so I don’t exactly know the answer to your question. Judith is credited on Discogs as on vocals only and in a MVs you can find on the internet, she doesn’t see to be pictured as playing an instrument. I did spot a glimpse of her playing an acoustic guitar in some gig footage, when I went look for it, just now.