I have engine oil all over the back of my car after a bad leak which occurred on a long journey.

Cars fixed but still dirty.

I'd really like a Step by step guide for safe but thorough removal please. 

I'm all out of tardis so other suggestions would be handy. 

I have most generic products to hand and also some auto glym engine cleaner and degreaser

spray but is it safe for paint? Can't see anything on the label that says either yes or no for certain.

What about APC? Also have BH and Valet pro snowfoam or do I just need very hot and soapy water.

It's pretty clean oil, pale brown not black. The car was only serviced about 1k prior to the leak. 

Your existing degreaser is paint safe...so use that

Wash off fully with APC and snow foam mix and a good wash with your usual car shampoo

Then reapply your wax or sealer....though you have an opportunity to re-polish too if you want, first

Cheers Chris...