Hi tiffy
For info purposes, the premises should have been fully surveyed at/and during the PON build. Ergo, the 3 x premises you mention whose duct only extend 'box-to-curtilage', wont have been overlooked.
OR's remit is (as mooted), to overlay the FTTP network following the copper footprint as close as is possible, barring grey areas. That means the infrastructure 'job' if you like, stops at the CBT. What the on-site surveyor will capture though are 'Survey Network Notes' markers against each individual premises ....... ie: overhead span no issues, overhead span through trees, overhead span road crossing, underground cable no duct ..... etc etc ..... there are lots of different markers.
These SNN files are loaded up at the final commissioning stage, so that when the PON becomes CRFS (Customer Ready For Service), the ISP's and the Stage 1 OR engineers who are performing the work, know what they are going into. It makes for a better customer experience.
Cheers.