RAF cutlery

I have lovely silver-plated cutlery which are very heavy and have an interesting hallmarks. Someone told me that they are silver but I think that they are silverplated (epsn). However they are very easy to work with ( i make jewelleries from the cutlery) and I would like to know if anyone could explain me why they have such a long serial numbers?? and as I can say that British epsn cutlery is very hard to work with and these are not , and they are form Britain, The pattern is called TAIL . I would be very happy if someone coukd advice me . :smiley:
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