Up/down beds for disabled bods

My mother has very limited walking ability, and recently this has been made worse by a blood clot ( knee to thigh ). The offending leg is huge - and very heavy and she can't lift it into bed. NHS have given her a handle to haul herself in and she has a strap. But the leg is too heavy.

I understand there are beds which lower to get in and the raise to help getting up.

Has anyone any experience of them? What sort? And where to get them? I thought I'd try the Red Cross next week but no real idea where to start.