Hello, I am a solicitor with 20 years experience. I will try to help you with this.
Can you tell me do you own and live in the same house? Is there a written agreement with the person in the former spare room. Does he py rent and f so how often and deos he have exclusive possession of the room, ie do you have any right to go into that room?
I do not live in the property there is no agreement with the lodger only with the 3 people who live there.. He pays the rent monthly and has exclusive possession of the room and the share of the kitchen, bathroom etc
Ok then, he is almost certainly a a tenant not a lodger. I assume there is no written agreement. He will also be an assured shorthold tenant so you will need to serve a S21 notice and give him 2 months notice.