Thanks for the replies, EFLImpudence is correct the sleeve isn't on the cable which goes to the switch on the wall. I know this is the cable to the switch as it has been recently chased into the wall and is still waiting to be plastered.
I would normally ask my electrician friend but he is on...
I am in the process of replacing a single light in the hallway to a couple of downlights. The ceiling has been taken down but the wiring was put into connector blocks without me seeing it and here is my problem.
I can see the swtich wire coming from the wall to the where the ceiling rose was...