Physical install flexibiity of engineers, your experiences?

[#1]

@starfry  the inside/out cable is about 5mm external diameter, once inside you house they strip off the external protection to leave a very thin white cable.  The cable has a pre-fitted connector (that plugs into the ONT) so the cable needs to pulled from the inside to the outside.

I only used the 25mm conduit as I was thinking I might also try to run an external cat6 cable through the duct as well in future for a cctv camera, but don't think that will happen now..

This is the conduit I used, but it might be best to try and find something with a smooth internal bore if it is long or there are a number of bends to go round.   My run was 7 to 8 meters with 4 x 90deg bends, obviously ensure there is a draw string in the duct before installing the duct.   Hopefully you'll get a good/helpful OR engineer and not a "jobs worth."

[#2]

I have trunking all over my living room hiding sat TV coax, speaker cables and network cables.
At the point of entry the fibre cable would fit into my trunking and the OR engineer was also happy to run the cable through it.
I also had FTTP installed for my nephew and the the point of entry for the copper cable, there wasn't a mains socket available and he was happy to run it a bit further into the living room.
Years ago with an ex, we moved to North London and I wanted the master socket in a spare bedroom which was used as an office. It was quite a long cable run and he was fine doing it.
Too be honest I've never had an OR engineer who was difficult about running cables.