We use Vuflex products, FR5200 is a fire retardent backlit pvc for digital at around £2 per sq mtr. Trouble you’ll have is getting the amount you need for the sign as normally you’ll have to buy a roll @ 50m. I think some suppliers will do smaller amounts but I’m not sure as we always buy in bulk. For applying vinyl graphics to PVC we have used the MacSoft range from Amari in the past. If you struggle to get hold of a set amount post back with your number and I’ll send you the amount you need.