Good luck with preparations for your trip, Paolo, and for the trip itself.
Here’s a UK lock that might interest you, made by Milenco… https://tinyurl.com/y3tz8ayc
I think the lock specially made for ‘our’ Fiat front doors by HEOsafe is no longer commonly available, but try these people… https://tinyurl.com/y369b2xz
Keep in touch and let us know how your modifications are going, with details of how you carried them out?
Good luck.
Barry