OP you don't say where you are local to, so that might help.
TBH tho (MFL specialist here) I would not base my choice of schools on this as you may find it is extremely limiting.
In 2018 only about 32000 students took GCSE in any MFL apart from German, French or Spanish - so that would include Urdu and Punjabi, both of which are quite popular in areas where they are the tongue spoken at home, as well as Italian, Russian and Mandarin. About half of those were taken in year 10, which suggests (to me at any rate) that they were taken outside school, early, in other words by students who spoke the language at home and did the GCSE as an early entrant, perhaps entirely out of school.
So we are talking about perhaps 15,000 students in year 11 taking a different MFL. So perhaps (random figure) 3,000 taking Italian in school - if that many, as I know of schools that offer Punjabi, Urdu and Mandarin, but I do not know personally of any that offer Italian (obviously some will of course, but it suggests that this is a less popular offering). Say it's 2,000. That is a tiny tiny number.
If Italian is important to your family, it might be easier to source a tutor familiar with the exam and study at home for an external entry, and then find a Catholic school that suits in other ways.