You sure about that sounds more like regs for hotels than residential properties.
The emergency exit would be the velux windows.
I'm a town planner, not a building standards officer, but I know he's correct about the fire regulations information. In addition to fire doors there also need to be a specific distance between the door and first stair (I think it's 1.2 metres, in Scotland at least). A rooflight (a la Velux) can be used as an emergency exit window, but it has to be of an adequate size and specific height above the ground (the specific sizes/distances escape me here).
I appreciate that the OP is no longer looking at the property, and therefore a loft conversion. However, it is worth noting that you do not need planning permission for works that are entirely internal and where there is no development that breaks through the roof line by more than 10cm (unless it's a Listed Building, where Listed Building Consent is required). So 'Velux' windows are permitted development and do not require permission, but a dormer window would, for example.
For a loft conversion, in most cases, you need only to satisfy the building regulations. These regulations have been upgraded lately and that
may make it more difficult to conform to them.
Edit: Ah, it appears LOAm has given the specific height/distances for an escape window
