Billy,
im sorry you are having to go through all this - buying from an approved dealer should be relatively stress free!
Anyway, just a couple of points. On the service history you list for your car, there's a 25month gap and 13,500 miles between service 1 and 2 - that seems a big gap to me - i dont know what the intervals are on long life but a car using the same oil for 2 years does fill me with confidence...
My second point is driving with low levels of oil - as someone has already mentioned, i would be worried about the unseen damage that may already have occurred to the internals. Surely if the dealership failed to check the oil level, it begs the question of what else they have failed to check? in my opinion, if you are going to be paying the premium for buying from an approved dealer, i expect the best level of service and the car to be tip top.
They can offer to do as many oil services they want but the damage could already have been done and sods law, the engine suffers a catastrophic failure in 12months and 1 week - landing you with a hefty bill.
If it was me, i couldnt live with that niggling doubt in my mind, expecting the worse every time i start the car up. I would take the chance whilst you still have it and take it back for a full refund. i know that perhaps your heart is over ruling your head (i understand the lure of the Eddy!) but there plenty of clean, decent examples of Edition 30's out there!
Sorry for the scare mongering, i just dont want you to suffer even more stress if things go wrong in the future.
Just my 2 pence!
Rich