well well well some time on and it was all ok in my loft...
what we did in the end was remove all the old stuff and dump,
remove rear chimney and repair the roof, also at the same time fit 2 roof tiles (vents) to the rear of the house , and to the front of the house we fitted soffit vents and all seamed to be great..
until we went in the loft for the Xmas decorations.
it smelt a little damp and we could see some condensation, we have moved the loft hatch in the past and i feel it could be that, as it seams to have some small holes around the joints that need to be fixed (yet another job i did not finish)..
so i have no fixed the bits around the hatch and will monitor the area...
simon