I did wonder about that Hugh, and i have felt behind the gutter but it feels dry!
Yes will get it re-roofed in the spring so just want a temp repair now.
It looks like a bit of a Clapham Junction of upstands, ridges and valleys ... the water could be getting under the felt from anywhere TBH ... also the right hand section of tiled roof appears to be very low pitch in the last photo resulting in water being blown under the tiles