I just talked to a guy at a tyre place about using the alloys off my now scrapped 57 TDCi Zetec Fiesta to eventually put winter tyres on (whilst I was having other stuff done) and he tried one of the 57 wheels on my 16 TDCi Zetec Fiesta and said that I would have to get the appropriate wheel nuts as they did not fit properly - something about the diameter of the taper, if I remember correctly. He said that I should not have any trouble getting the nuts if I used the information on the inside of the alloy (see photo) but none of it makes much sense to me and when I put the registration numbers in when searching for wheel nuts, the exact same items come up for each car.

I was under the impression that Fiesta wheels were pretty much interchangeable and had put the previous winter wheels on steel rims from the 57 on my girlfriend's 15 Fiesta oblivious to any possible problems.

I'm confused!

The later models use global nuts.  You need the old style nuts.

Global nuts have a bulge on top.  Old nuts are flat on top.

Thanks. I'll have another search.

Hmmm...

Do you mean literally with a dome or just a round top. I can't find anything with a hexagonal profile all the way to the top - those which don't have a dome still have a circular bit at the top, as per enclosed photo.

Never mind, I think I have found some like your photo which mention Cortina, Escort and Mondeo in the title so I guess they are the old style.

Those are different again, you need solid nuts, not the spinning washer type.

The top difference only applies to the genuine nuts.  You have to be very careful choosing aftermarket nuts.

These are the exact ones you need.  Not suggesting you pay that price for them, just for comparison.

https://www.ebay.co.uk/itm/393525337553?