Thanks chaps for the input . On your good advice we have phoned the building inspector and arranging for him to visit , think he said the cost is £81 as said above , but he did mention something about the doors also need certificating if they are over 50% glass area , which they all are .
My concern now is if they happen to fail inspection ! Does this mean they will all need to be ripped out and replaced . not being familiar with building regs so no idea what they mean by installed correctly , do they mean fitted upside down or back to front or something ?
All I can say is that talking to the guy when he fitted them he seemed to me to know his job , I saw the work done and from my eyes it all seemed OK so would be very surprised if they were rejected, but got to admit it is a bit of a worry .
Just to add we had the property refurbished with a view to letting so the windows had to have openings that allowed evacuation in the event of fire , not sure if there was anything else special about them but one thing , being a bungalow there are no lintels fitted just 2 coarses of brick above each window , every property on this estate was built the same .