Here in England, we have many shi’as who support the english football team. After their loss to Italy, i have seen many of them send lanat to Italy. Is it permissible to send lanat on Italy due to them beating England in the Euros?

No it is not permissible to send such la’nat. It is only permissible to send la’nat on corrupt individuals and disbelievers. Sending la’nat on an entire nation is not permissible since there are good people there.