Defnyddiodd Llywodraeth Cymru broses deialog gystadleuol i ddatblygu a mireinio’r cynigion cychwynnol a gafwyd gan bob un o’r ymgeiswyr, a ddatblygodd eu cynigion i wahanol gamau. Gadawodd Thales y broses ym mis Gorffennaf 2011, Geo Networks ym mis Medi 2011, consortiwm Balfour Beatty ym mis Rhagfyr 2011 a Fujitsu ym mis Ionawr 2012, oedd yn golygu mai dim ond BT oedd ar ôl yn y gystadleuaeth.
The Welsh Government used a process of competitive dialogue to develop and refine the initial proposals received from each of the bidders, who progressed their proposals to various stages of development. Thales left the process in July 2011, Geo Networks in September 2011, the Balfour Beatty led consortium left in December 2011 and Fujitsu left the process in January 2012, leaving BT as the only remaining participant in the competition.