Hi All
I would say first thing is to always double-check Fuel SD page by pressing and holding the Fuel button on ECAM switching panel so it appears on upper ECAM screen (as total fuel on board indications on EWD will be lost until FAC 1reset). This ensures you use the right checklist! (Fuel remaining OR No Fuel Remaining).
As a pilot who flies A320s with both engine types, the IAE engines have an optimum re-light speed of 280kts, whereas the CFM engines have a higher re-light speed of 300kts.
With CFM engines, this means that with a dual engine failure in a cruise at high altitude, the optimum relight speed may be quite a way above MMO, and a progressive increase in speed towards 300kts during the descent may be required to avoid exceeding MMO.
Pro Spin.