We have some 5mm thick rubber underlay for carpet which was laid in a room measuring 3.65 x 3.05 so over 10 square metres of it. Most in good condition and still holds its shape, one section is a bit dusty and there are a couple of tears (one is quite long) but it still fits togther so you can use it torn. It's still in the lengths and widths it was laid in so could be reused. Rolled up ready to collect.
We also have a) a piece of 1cm thick foam carpet underlay, haven't measured but maybe 2m by 1m, and b) the old cream polyester carpet in poor condition and cut into strips of over a metre wide in the unlikely event that's any use to anyone.
Collect from Moseley near Ladypool Road.