BBD
OPS 1.800 does not say "if the aircraft is designed having such specific areas...."
This EU OPS rule originates from the followingICAO Annex 6 Part 1 again no mention of design.
6.2.4 Marking of break-in points
6.2.4.1 If areas of the fuselage suitable for break-in by
rescue crews in emergency are marked on an aeroplane such
areas shall be marked as shown below (see figure following).
The colour of the markings shall be red or yellow, and if
necessary they shall be outlined in white to contrast with the
background.
Inbalance,
I would challenge the finding and seek assistance from your Regulatory Ops inspector as they cleared you to operate without such markings.