A very quick search for "2010 XF used engine" returned at least a couple results from one source for less than $6000 (not sure which of the 2010 XF engines you have. they list 4 possible). There are likely many places and many prices for engines of various ages/miles. It was a used engine when you bought the car, anyway, so why not replace in kind, keeping as much of the blown engine for future parts as you can, especially if it can save you maybe $20-25K compared to the cost for new?
As an aside, something(s) seems odd...you said after the shutdown you got the car to "turn over" (meaning it rotated without starting?) so you could get it into neutral... I'm not sure how the engine rotating or not could prevent selecting neutral whether manual or auto transmission. Somebody who knows (I don't) will have to verify that yours is an 'interference' type engine which I think would/could make cranking it over impossible if the timing chain was off....and if it started, this engine could run after the timing chain "came off"?
