Have a look at this
I've used these guys 4 or 5 times now. I have always for some reason been quoted a cheaper price when I call in and ask for a quote (£45 last time - June 2012). Car has now done 137k miles (131k with me at the wheel) and seems to be going strong. I have never bothered providing OEM filter as Unipart has to be good enough.
National do use Castrol Edge LL04 Oil as prescribed by BMW
F10 530d M Sport, September 2012 Individual Amazonite Silver, Oyster Dakota Leather, Auto, Nav Pro, Bluetooth + USB Devices, Expanded BMW Online, Comfort Seats, Sunroof, Sun Protection Glass Individual Satin Walnut Honey Brown Trim Interior Inside/Outside Mirror with folding and autodip, M Rear Spoiler