The Solemn Liturgy on Good Friday is a remarkable and complex thing, going through distinct phases with the clergy in different atire at different stages. I'm not qualified to do a commentary but I've given some indication of what is going. See also my Flickr set.
The minsters prostrate themselves at the start of the liturgy.
The sing the Passion of St John.
The Great Intercessions.
The Creeping to the Cross.
The Blessed Sacrament is brought from the Altar of Repose.
Ecce Agnus Dei: the 'Mass of the Pre-Sanctified'.
Fr Leworthy was celebrant, and Fr de Malleray was deacon; the Rev Mr Sypher was subdeacon.