Rethink are a brilliant organisation. In Dorset they are really only involved with the support of carers of those with mental illness but they do some great work in this respect. In many places around the country they are involved with peer support and provide support workers. I was lucky enough to have a support worker just before they had to withdraw from Dorset back in 2018 and this was a fantastic service.
See some of their latest, very informative newsletter here.