Hi Susie, You would be best speaking to a roofer. I would assay you are on the right track with ventilation it is more than likely new loft insulation is what is causing your problem. It is a relatively easy fix at around £60.00 per tile. However it would also depend on access to your roof.
Hi susie I would recommend you get a few differnt roofing firms inn to have a look at the job nearly every firm now provides free quotions so it should not cost you anything and this way you will get a few differnt apinions on how to solve this problem. Many thanks Scott
Hi there Susie, I would contact a roofer for this issue. It could be a simple issue of fitting a few vent tiles to the property, depending on the condition of the felt. If the felt has deteriorated i would advise re felting and battening the roof.