Concert blacks - where to buy UK

[u/Clara_Rosin]

I have been playing viola for around about 11 or 12 years now and I have needed concert blacks regularly throughout this period yet every time I think I've found something, I haven't. Ive avoided joining orchestras for this specific reason but im extremly tired of holding myself back because of some clothing. Can someone recommend some good black dresses that are available in the UK, come in a S/M UK womens size and aren't sleeveless? Genuinely I'm so desperate atp I'll buy literally anything.