I always forget the London Oratory is actually state (formerly voluntary aided now an academy I see) - I confuse it with its Berkshire sister, which isn't. I'm not too clear on the structure but my understanding is it's controlled by the Oratory Fathers and only indirectly answers to the Diocesan Education Service. If that's right I suspect it would have stayed pretty conservative throughout, as they did. The Oratory itself (admittedly a different physical site) certainly had regular old rite masses by the early 90s and I think took advantage of the indult to retain them from the start, as well as modern rite Latin with all conceivable bells and whistles at the main services.