Further into the clear out I've found some of those circular white plastic eaves vents which allow air to circulate up the rafters, over the top and down the other side. Hole saw as well.
Intended, I think, for boarded over loft ceilings where there is a risk of condensation next to the roof.
Looking around, nobody seems to have them in this row of houses.
Are they still considered to be a good idea?
Cheers
Dave R