Hi. I installed one in a bathroom where there wasn’t enough space for a full bath as I prefer a bath; a year later I pulled it all apart to install a shower!
You can only fill it up to the height of the seat so you can only wash your legs up to your knees, forget about the rest! Unless you squat down in the well where your feet go you won’t be able to wash properly. If you think getting out of the bath now is a problem, try squatting in a third of it and then try to get out! Never again will I install one.
Keep your full bath, you can affix hand grips to assist you when getting out and Help the Aged can advise you of various solutions they have, I know there is a seat that raises and lowers you into the bath. Alternatively there might be a grant available to replace the bath with a shower?
Best of luck