There is a further statement on their website now, 'beef with the landlord' doesn't really do the situation any favours. I do hope they can continue to be a good resource. The pandemic appears to be the final nail in the coffin for many an independent. Shame.
https://www.theguardian.com/books/2021/dec/29/uk-first-specialist-black-bookshop-shut-new-beacon-dismay
I hate it so much when shops like that close. It's not one I ever went to, but it's something I've experienced with plenty of other places.