Welcome to Dementia Taking Point @Tigga2.
If you have Lasting Power of Attorney and the person that is moving into care has lost capacity and also has the funds to pay for care you can start looking for care homes off your own bat. If you will need social services to pay for care you need to contact them and start the ball rolling.
This website https://www.carehome.co.uk/ might be useful if you are looking for a care home. Even if you will need social services input it'll give you a good idea about what is out there. When I first thought my mum was moving towards needing to be in care, a good eighteen months before it actually happened, I started by visiting a few local homes to see what they were like. Although reviews and CQC reports are useful nothing beats going and looking for yourself. Not all homes are alike, and what will suit one person won't another.