Cheers for the responses - thought I was worrying too much.
They dont know what it is as they have only just moved in (from being our next door neighbours to being 3 doors away
)
Its on underlay and gripper and is high % wool from burn test.
My worry was that every so often in the backing there appears to be a different fibre going across - above the hessian as it were.
I thought that these could still cause problems if they had jute in the backing? If its only woven then happy days.
Thanks
Simon