The average price of an oil and filter change is around £100. If you choose a franchise or dealer to carry out the work, you can expect to pay anywhere from £70 or £80 up to £160. Your local mechanic will do it for less, of course; between £50 and £75 is pretty reasonable. As you aren't within your car's warranty period, I'd probably just opt to go to a reputable independent garage to get it done.