Cathedral Music Associations
These are all based in the UK.
Friends of Cathedral Music
You are in the links section of the Friends of Cathedral Music website.
The Federation of Cathedral Old Choristers’ Associations
The Federation of Cathedral Old Choristers’ Associations "Consists of Old Chorister Associations from Cathedrals throughout the British Isles, Eire and New Zealand ... The objects are primarily to promote friendship amongst people from like backgrounds, to assist in maintaining and improving the high standard of cathedral music that plays such a vital part in cathedral worship, to support and encourage the activities of each Association and to bring them together in closer contact with one another."
Campaign for the Traditional Cathedral Choir
The objectives of the Campaign for the Traditional Cathedral Choir are "To champion the ancient tradition of the all-male choir in Cathedrals, Chapels Royal, Collegiate Churches, University Chapels and similar ecclesiastical choral foundations. It is also the policy of CTCC to encourage parish churches which maintain, or seek to establish, all-male choirs."