I've had a bit of a look around for spray foam insulation.
Just found
http://www.foam-insulation.co.uk (0800 019 6064)
Rigid polyurethane spray foam is effective in controlling condensation on metal roofing by creating a warm roof resulting in excellent thermal and sound
insulation. Because the IsoSpray spray foam insulation can be applied direct to the substrate surface, it is excellent for metal cladding insulation and
asbestos cladding insulation on industrial buildings and farm buildings
I've not had any dealing with the company so I don't know what they are like, but the product sounds the right kind of stuff.
T.