Having developed the upper floors of the property into student accommodation 2 years ago which are fire alarmed, we are now developing the ground floor into a shop and flat. I need advice on appropriate fire safety to link all 3 aspects of the property.

This will need Building Regulations approval therefore the fire safety should be in accordance with Approved Document Part B Fire Safety. When the building work has been signed off you will be subject to the The Regulatory Reform (Fire Safety) Order 2005 and guidance will be Offices and shops and Sleeping accommodation.

Check out http://www.firesafe.org.uk/regulatory-reform-fire-safety-order-2005/and http://www.firesafe.org.uk.