i have a 2013 astra gtc needs back fog light bulb replaced .cant seem to find out the correct bulb for it.been to local vauxhall dealer they dont have one and looked a bit stumped by it .so if anyone knows the type please let me know .was looking on line for 1 it looks like a pg20-7 psx24 but i dont know if it would fit.they are about a tenner so dont want to buy only to find out its no use