1974 Europa TC, 1990 Esprit SE, 2003 Esprit V8, 2005 Elise
If the engine is in the car then I would remove the spark plugs and very gently and slowly back it up to the original "Safe" position. With the plugs out the engine should move very freely and with enough caution you should be able to feel any obstructions pretty early. Slow and with great caution. If anything gets bent the engine is coming out. There are probably others who would recommend otherwise but this is probably what I would try first.