A very exciting car, if as claimed. I wonder who bought it to the UK, and why they would they let such a prize go? Perhaps the answer to that is the Sept. 2021 recommissioning work costing E5600. Perhaps the cost of sorting the car out properly was simply too daunting...
Results of some Google research:
https://www.racingsportscars.com/race/Mille_Miglia-1952-05-04.htmlTurismo Nazionale oltre 1500: 249 Lancia Aurelia B21 Maglioli / Monteferrario
Registration VC 27997
So the win was in the 'Turismo Nazionale oltre 1500', not Gran Turismo class as stated in the auction listing. The Gran Turismo Internazionale classes were won by an Aston DB2, a B20, Porsche 356 and DB Panhard X86.
And the car is, in the competition results, listed as a B21, not B10. This discrepancy could be caused by the factory swap to a B21 engine (and possibly transaxle) before the '52 MM.
They key is the paperwork with the car, which on the face of it sounds convincing.
I suspect it will go for substantially more than the top estimate. A dealer in the Netherlands (I think) had a B21 with MM history a few years ago that they were retailing for (from memory) about E70k.
P.S. Did Magioli lose the front bumper during the race? It's on one photo of the car with its 249 number, but not in the photo of the race's finish.