We have a soundproof green screen studio located in Central London complete with lighting here:
https://bloomsburyfilmstudio.co.uk from £450 ex VAT per day. Located in Bloomsbury, right near Russell Square station and convenient for Euston and Kings Cross. Save on taxis for talent!
Else you can hire a portable green screen stand from us for £30 that folds away into a collapsable frame. This has a highly saturated green cloth perfect for chromakey application and large enough to get a person standing in front of.