Our buyer's lender's surveyor asked us to remove the rigid foam insulation from loft (applied by previous owners 12+ years ago) as the lender won't lend due to fire risk. The foam is directly on top of the roof tiles (with no membrane/material underneath). Been a nightmare as it took weeks for contractors to remove the residue from the loft (from cutting and scraping it off). Upon re-inspection the surveyor is still not satisfied with the removal as there is residue of the foam left (stuck to roof tiles). Can this residue still be considered fire-risk? Is the surveyor being unreasonable? Any advise please on how best to remove it if possible? Looked into dry ice blasting but there is a risk of it dislodging and damaging the roof tiles (especially as some tiles with hairline cracks already)

Refer to the answer above.

If you get the answer you seek, then what?  The surveyor is clearly on the side of caution (But it may be the foam is flammable) I would also ask, since some of the tiles have hairline cracks how much would a new roof with under felt cost and how much would dry ice blasting cost?