I am trying to fit a ceiling light to my ceiling. The mains cable running through the ceiling joist is too short to reach the ceiling light. The light fitting has a 3 block strip connector to connect the mains to it. Is it OK to feed the flex from the light fitting up through the joist and connect it to the short mains cable. This way the conection will be made in the ceiling cavity. I can access the cabling from the floor boards in the bedroom. There is no insulation i the ceiling cavity so there is space for the connection to be made.