the oil will indeed seep out, including the oil you wish will give some kind of protection (and I know it used to be done years ago by
brushing on to surfaces).
The
Bilt Hamber product mentioned above will be cheaper than the environmental agency fine, as well as being quicker than making a rig to clean/collect the draining oil, waiting for it to drain/dry. As well as that, the S50 should come with a 360 degree lance to make it feasible to upper edges of the sills, and the S50 doesnt risk spilling out whilst you are driving on the road - so safer for others.