leak...see video...where would leak be? http://www.youtube.com/watch?v=D2yhs54fETI

It sounds like the bottom of your felt has rotted away, you can get some gutter refurbishment trays, come in 1.5m lengths, remove bottom rows of tiles, slide the trays up under the felt with the curved edge into the gutter. Retile back over. Edit to your last post; Sorry I live in the Cotswolds, if you post your requirements in the post a job section, you will be sure to find a tradesmen to carry out the works for you.

Hi looking at your video it looks like your fascia may of been over cladded at some point,if so this could be the reason why the water is getting behind guttering....originally your roof slates would of started of at a certain gauge,this gives the bottom of your roof slates enough overhang to let rain water into guttering usually 1" to 3" but if the overhang is short and with the 10 to 15mm that would of been added with fascia cappit there maybe a chance of rainwater getting behind guttering rather than into it. Hope this has been helpful Frank

i would say you may have a broken slate or simlair problem, as the slates should keep the water out regardless if there is felt on a roof or not. felt would only ever act as a second line of defence. there are many old roofs with no felt that dont leak