I may be wrong but I think MrT is able to contact him, judging by a response from him on page 8 of this thread.
Edited to add that I've just messaged MrT, so we may know shortly.
Mr Dracott's views would certainly be a great help in identifying the major differences.
The 1854 no colons penny is decidedly scarce if not rare.
Maybe once or twice a year, an example will present itself somewhere, generally in worn condition.
Depends on when they were made. Prior to 1883, aluminium was not commercially available and effectively a precious metal given the cost of extraction and refining. I'd say nickel or tin were more likely in this instance. Tin plating is surely the cheapest method.