Salvo servicio nostro. In cujus rei, etc. Testibus ut Supra. Apud Dunbrettan, duodecimo die Novembris anno regni nostri terciodecimo. The text is obviously a charter given by King Robert of Scotland.
Some errors appear to have crept into the text.
Tenendus should be Tenendas, per omnibus should be per omnes, per is always followed by the accusative case. Necnon can be negative or positive. Here it is obviously positive, Continit should be Continet. Silver on a blue cross, between an eagle, at the top a green serpent at the bottom a silver bird. A phoenix proper.