I live in a three storey house and the bottom floor used to be a shop.i have got change of use permission to turn it back into residential and have got building reg to come round and look at what I am changing. I need to remove two large windows and put smaller dg windows in and brick up to suit. All pretty straight forward but when I have removed the plaster from round one of the windows I have noticed it has a wooden lintel which also supports the floor above I.e joists sit on it.the lintel is in very good condition no signs of rot it is bone dry and solid.my worry is will building control want me to change this or is it ok to leave in.