Hi all
Havent had my Punto long & got a flat tyre. Went to change the tyre, the 3 normal nuts came off no problem, but the 4th one is different like a security type one which wont come off with a normal socket. Went to Kwik Fit who 'helpfully' suggested whacking it with a hammer which I dont want to do! Where can I find the special socket?!!!
(not sure if it matters but they are 17" Stilo "claw" type alloys)

locking nut tool is ofted in glove box, ot in the holder where the jack is.

have a real good look around for the locking wheel nut, hassle if you don't have it.

If its a fiat locking bolt, you might be able to order a duplicate (only guessing)

Otherwise, get the hammer out

here's a guide on taking it out with a hammer:
https://www.fiatforum.com/miscellaneous-guides/128372-removing-locking-bolt-without-locking-nut.html