A retirement home is not the same as a care home.
They tend to be complexes / blocks with apartments that only people above 55+ can buy. They do not employ carers and the residents are still expected to be self sufficient with cooking, cleaning, laundry etc. However the apartments are only owned leasehold and the service charges (like any leasehold) are extortionate.
McCarthy Stone are a massive retirement homes company, here are their charges as an example -
https://www.mccarthyandstone.co.uk/what-we-offer/services/service-charge/ (for the mid-range complexes, they charge £183/week).
Care homes are something else entirely, where they have a 24 hour care staff on site for helping people with eating, washing themselves etc.