Re your query about building control yes you should contact building control particularly if you wish to sell your flat at a later date but if your father in law is a builder he should know that. Your current room layout would appear to be to provide fire protection between the kitchen and the bedrooms/bedroom, living room. Also are you sure the original layout had a through lounge? Is this the ground floor of a Victorian house? If so although the internal cross wall is structural even if it is a stud wall. It takes the weight of the floors above and part of the roof.
Lastly if it is a flat you will need to agree any changes with the freeholder.
Trunkie,
Re your query about building control yes you should contact building control particularly if you wish to sell your flat at a later date but if your father in law is a builder he should know that. Your current room layout would appear to be to provide fire protection between the kitchen and the bedrooms/bedroom, living room. Also are you sure the original layout had a through lounge? Is this the ground floor of a Victorian house? If so although the internal cross wall is structural even if it is a stud wall. It takes the weight of the floors above and part of the roof.
Lastly if it is a flat you will need to agree any changes with the freeholder.