This is something that surprises me about student accommodation: it used to be dirt cheap as students weren't expected to live somewhere posh. In my last year at uni, I paid £25 (£102 adjusted for inflation) a month. The owners are charging tenants £600 a month for the house next door to ours...
I don't know about Lewes but B&H Council is definitely keen on having fewer HMOs and more students on campus. I'd be surprised if LDC had a contrary view