Reading 20.7.1B, 7 Take-off climb performance
The CAO never mentions the term "segment" for what we all refer to as 1st, 2nd, 3rd, 4th segment.
7.3.1 and 7.32 refer to the "level flight acceleration manoeuvre", what we'd call 3rd segment, as commencing at a minimum of 400ft.
7.4.1 and 7.4.2 refer to the "en-route configuration" starting at the end of that level flight acceleration - so can be understood to also start at a minimum of 400ft.
Going back to 7.2, it describes the aircraft with gear retracted and at V2. This is what we call 2nd segment and can be understood as stating from establishing in that configuration.
And then back to 7.1.
It states " In the take-off configuration assuming failure of the critical engine so that it is recognised at V1, an aeroplane must be able to climb without ground effect at the speed established as the speed at which the aeroplane becomes airborne and in this configuration, without landing gear retraction, achieve a gross gradient of climb which is positive for two-engined aeroplanes ...".
Not referred to as "first segment", not given a starting height. There is nothing here that states "commences only at 35ft" or "commencing from the end of TOD". This states that the aircraft must be able to climb at VR.
The implication is that the flight path from runway to 35ft (and onwards to completion of gear retraction), where the aircraft starts that manoeuvre at VR must be positive (twin engine aircraft). Notice how between 7.1 and 7.2 there is no mention of acceleration from VR to V2. The CAO states that the"first segment" consideration is solely for climb potential at the speed of VR, it is not an accelerating segment. In any aircraft this "first segment" consideration would extend until the gear is fully retracted (regardless of if it's a slow retraction or not), and only after that point would the "second segment" consideration begin.
But also "first segment" consideration must apply from the moment the aircraft leaves the ground (which would be within the "up to 35ft" area defined by the TOD) as the CAO doesn't mention anything that can be taken to suggest otherwise.