Who might claim to have actually written the language I don't know, except that it was on the side of the Juncker and small-country camp, and certainly not the A-B-C camp (Aznar-Blair-Chirac). And the Juncker side was/is certainly not in favour of a powerful president of the European Council also taking over the attributions of the Commission president. So I don't know who or what Ivor Roberts is talking about.
Pierre Lequiller, representative of the [French] National Assembly in the Convention, suggested for example a single president of the European Council and of the Commission.