Could be many reasons. For example, the properties with pots (aka 'toby boxes') could have DIG lead-ins, whilst yours has a proper Openreach duct which Gigaclear are happy to re-use.
We're presently served by an Openreach pole and overhead copper wire (the existing ducting is just between the cabinets and poles, etc). And this is true for most of the houses in the area. That's what makes it even weirder on one level: everybody else (who are also presently served by overhead copper) is getting underground fibre, whereas assuming the ten or so houses near us get anything at all it looks like it will be overhead, via the existing OR poles.
To somebody on the ground there's nothing obviously different or more difficult about our part of the lane. And it's not obvious that the Openreach infrastructure is in any way superior to the rest of the area. So it makes me think there's a subtle technical or legal reason that forced them to treat our bit of the lane differently, but I can't figure out what it might be. There is National Trust land on both sides, but the NT open data portal suggests they don't actually own the road itself. So who knows.
Of course, it ultimately doesn't matter what the actual reason is... but I'd still like to know