If I have an exit closed off for a few months in a licenced premises and the exit now directs people into a building to an emergency exit and the distance is 40/50 metres. Is this legal?
It could take them towards a fire and not away from it.
People will, as you know just follow signs and they would not know where the fire was.
This involves 2 rooms that can hold 60 each.

Without a lot more information I cannot give a definitive answer but 40/50 meters does seem excessive and is there an alternative means of escape. I would suggest you have an Fire Risk assessment done to conform to The Regulatory Reform (Fire Safety) Order 2005 the appropriate guide is Small and medium places of assembly.