The Church of England have published their own guidance on ringing and is here : Guidance for parish churches on the death of HM the Queen 8th September 2022.pdf (churchofengland.org). Doesn’t contradict the CC email.
One thing to note in this is that D Day is tomorrow (9 September) and not today (8/9/22)…. The first three pages of the document talk a lot about flags and ringing