Perhaps there was one at IOT (Feltwell, '65) but no recollection of the event.
Not a church parade as such, but after the passing out parade at Feltwell in 1964 most of the course, together with parents, wives etc repaired to the station church, while the handful of left footers (self included) went to the small RC church for our own service. Other than my sister in law's requiem mass in around 2005 it was the last RC Service I ever attended. Been to lots of C of E services since - the architecture and the singing are a lot better!