Gey-la is the usual pronunciation of gala in the north-east of England as in the Durham Miners' Gala (gey-la).

'Anglican' only refers to the Church of England and churches derived from it - most of which are members of the Anglican Communion. 'Anglican Church', although often used as such, is not a synonym for 'Church of England'. Outside of England it is often used as the title e.g. by the Anglican Church of Canada.

'Anglian' could be used as the adjective for things English generally, but is in practice only used in 'East Anglian'.

I remember an American newspaper article explaining that what Americans call the 'John' is known as the 'Claude' in Britain.