Self adhesive vinyl floor tiles are becoming one of my gaming ‘swiss army knives’ – I’m finding so much you can do with them, and the cheap ones are £2.50 for 6 30cm square ones (QD had packs for £1.50- but I don’t know how good the glue is compared to B&Q budget ones).  Sometimes people throw them away- they only needed 38, but had to buy 42- so you can get them free.  The secret is to use the adhesive side.