So I've had the second Gas Safe registered installer out. He thinks I should re-site the ventilation altogether otherwise I'll have a draught whipping round my feet. He hasn't said about whether having the tap below the floor is allowed because he's suggested chasing it into the side of the chimney breast with access via a hole in the skirting. It'll be sideways on and out of sight so that suits me.
Meanwhile I called the manufacturer about getting new coals. He reiterated that anything less than 7 kW doesn't require ventilation. He also told me that my type of fire is illegal because it has no fuel control.
The gasman today is prepared to work on the fire even without instruction but said it would need testing. But, as FiremanT pointed out, why not get a new more efficient fire. Then if I ensure it's less than 7 kW I won't have the hassle of another hole being knocked into my living room.
However I've read conflicting things, some say ALL DFE's need 100cm2 of ventilation, others say the manufacturer instructions take precedent. Can someone point me to the definitive regulation? Thanks.