Hello I'm spending the summer in

Yes!

there are no problems, however it is good, that your aunt, write a declaration, in Italian, in which she declares to have lent her car to you, for a certain period - something similar <me undersigned - name / surname, born a / il - date-, resident in xx - identity card or passport nr. xx - I declare that I have used my car for the period xx, license plate xx, my nepote name / surname - passport number - English citizen> If the Italian traffic police stop you, for a check, you you will be able to demonstrate that the car you drive has been entrusted to you by the legal owner and that it has not been stolen  Buone vacanze in Italia

Thank you so much, that puts my mind to rest x