In the quest for a Bristol engine for an Aceca Bristol, two (don't ask, it's a long story) ex-Greyhound engines came into my possession, neither of which were yours, though. Both needed full rebuilds. I eventually offered them to the then current owners of the Greyhounds, but neither was interested. One finally ended up in an Ace Bristol in Germany and the other in a Veritas in Austria. I didn't make a profit on either of them, not being a dealer. If I sold them today, though, it might be a different story...
I was overjoyed when the original engine for the Aceca became available and paid the asking price without demur, despite that needing a full rebuild too. Definitely worth seeking out the original engine, in my opinion.