Just thought about this again and remembered that I had to remove most of the exhaust system, up to the rear axle, to change my turdo.
I poured a lot of oil out and left the pipes draining overnight before building it all back up.
I was gutted when I saw all the thick smoke , it filled the street!
But, like I said, 10 miles and it was clear again.
Mine didn't run away like yours, the seal just went near to home but I was surprised how much oil was in the exhaust.
Yours would have a lot more and the garage may not have bothered to empty the exhaust and possibly your intercooler and hoses as well?