Building control - roof vents

nanny_bump

Morning. we've had a return single storey kitchen extension built on our terraced house with a flat roof but are now having a issue with building control about the roof ventilation before we can get it finally passed.
Our builder has put in 5 x 'mushroom' vents between the roof lights and original house but the building control manager from the private company we used is insisting we replace these mushrooms with 2 x long abutment vents before he will pass it.
Relations with our builder broke down before this final inspection so now looking to get a different roofer in if must go ahead with fitting abutment vents. This roofing company visited yesterday and said abutment vents seem unnecessary when these mushroom ones have been fitted...
Is there a way I can challenge the building control manager? He claims he told our original builder abutment vents on a previous site visit the abutment vents would be necessary but don't think this was put in writing. Building control has put the abutment requirement in their latest progress report.
Seems a subjective requirement that we could do without.
thanks in advance 

Mrcake

thousands of roofs are replaced every year because of condensation caused by bas ventilation, looks like your inspector knows his stuff and is saving you a major headache in a few years. By all means challenge it but make an alternative suggestion if you have one. The building inspector is probably professionally qualified and applying published rules (i just looked it up and is BS5250) - what is the roofers opinion based on any science at all or just a hunch?.