Stuck in a council flat that’s making my health worse?

Hey folks, I’m kinda desperate for advice. I’ve been a housing association tenant in Southwark for years, but my chronic back pain’s gotten worse, and my current flat is a nightmare—stairs everywhere, no lift, and the damp’s triggering my asthma. My GP says I need a ground-floor place ASAP, but my council claims there’s a 2-year waitlist. Has anyone managed to transfer boroughs for medical reasons? I tried applying online to Lambeth, but their portal kept crashing, and now I’m stuck in this loop of “submit again later.” Plus, my landlord’s being sketchy about giving permission for a mutual exchange. Am I missing a trick here? I can’t afford private rent, but this place is literally making me sick.