As no one answered about how to physically turn the engine easily, I found an answer myself. The answer is the starting handle. Presumably a lot of Aurelia owners will be missing their starter handle as I was. With the kind help of Chris Gawne, I found an anonymous one on ebay (for £18 including postage) that works perfectly. The bar should be 13mm dia and about 600mm (very long) in length to the 1st bend.
The cross pin (which engages the crank pulley ) is 28mm long, end to end, and 6.5mm diameter. I think my one may have been for something like a land rover, it certainly doesn't have to be a very expensive and rare Lancia one. Of course you can only turn the engine clockwise, but then I think that you are not supposed to turn it anti anyway?