He took the place of Stephen in the fifth series of the show. Liam is just trying to get a hand of these exciting things which are yet to happen to him but all of it is a mystery. Sometimes Liam can really not like the stuff the gang put him through, such as when the residents go to a haunted house, Liam and Basil waned nothing to do with it, and tried to escape. Only to mostly be stopped by Master Dave.
Basil does not call Liam under the name of "Mr Liam" as he did with Stephen. But then again, he never calls anyone "Mr, or Miss" like he did in the first four seasons.
Liam is also shown to be very loving, sometimes acting like the big brother to Lucy, and good friends with Dave, Molly, Basil and Anil.