My son wanted to build a model, so we picked one from the Battle Sister Squad I got years ago for a some forgotten project or other.
He chose the colours and did the base layers, I did the details and shading. He's very happy with her, the colours he chose work well despite being not at all Sororitassy. Adeptus Scotoritas with the flag cape he wanted (Order of St Margaret as suggested by @Karandrassh).
I tried to convince him he wanted an urban base so I could nick her as an Inquisitor or something on Necromunda, alas the kid thinks static grass is the bestest thing ever so we compromised on overgrown concrete.
Still going to pinch her.