lacroupade
Veteran
I've always used Commas Oils to great effect on my 4x4s, and since their oils are BMW-approved, this link might be useful to UK members - you just stick your reg and postcode in and it tells you the type and quantities of oil you need, plus your nearest distributor. Enjoy. 
http://www.commaoil.com/motorists
http://www.commaoil.com/motorists