I have 8 boards I have taken out of my roof space as I was adding some more insulation.
They are each approximately 4 feet (122 cm) by about 13 inches (33 cm). Hopefully you can see in the photos that they are grooved so they slot together.
Over 20 years old. You will probably need some long screws to fix them in place.
Loft boards (Kidlington OX5)
This offer has been gifted to someone and is no longer available.