Arit Eminue's reply:
Hi B. Brock,
I only recently received your query, so sorry for the delay in responding.
Have you tried the Creative Skillset Trainee Finder? http://creativeskillset.org/who_we_help/young_creative_talent/ways_creative_industries/trainee_finder
It is essentially a paid internship scheme for those looking to gain experience in TV and Film Production. They offer a variety of roles across the production grades. If you have not done so already, do create a profile on HiiVE where employers in film and tv advertise current vacancies. https://app.hiive.co.uk/talent/
Also, check out the Theatre Design Organisation.
I also encourage you to connect with organisations such as Film London and offer your services to filmmakers who are awarded funding under their Microwave Film Fund.
Hope that helps...