hey thank you for reference to handbook - very useful!

Not all 'new build' house builders do the internal cabling the same way so if its a solid floor they may have put a conduit in (if thats the way its been run) but I think you would need to do some investigation yourself before the FTTP installer arrives as theres no guarantee there will be time on the day to start looking for conduit runs if they are hidden under carpets or behind walls.

Are you sure it's fed from a duct popping up inside your house? I rented a 2002-build and the master phone socket was on an internal wall, but the BT duct still terminated on the front of the building - there was just a three pair phone cable run between those locations by the house builder.

It's probably worth trying to get the duct broken outside your property so that any gas leaks or issues with water in the BT network don't end up inside your house.

FYI - I have had a fair few new builds and one of them put the BT Duct in to terminate in a cupboard under the stairs (with power adjacent) - they had thought OR were going to put in FTTP - but that didn't happen (as the developer didn't want to fund it at the time!) but they still did the install in the same way. i.e. the copper came in via the duct under the stairs.
This was a cast concrete floor.

So as you say different ways of doing it.

ive never noticed any existing capping outside the property for the phone so i think it is ducted the whole way underground into the house?

see these photos of front external wall and master socket in lounge

https://ibb.co/DMbvp2X
https://ibb.co/tJTQLqw

The access panel to the side is for electricity/gas only?

yes this houses the electric meter - mind you i never thought to double check if any bt capping is inside too - would this be allowed or sensible - ie might cause interference?

I agree, I don't think it would be a good idea, but just wanted to check. It looks like the cable has to cross your hallway somehow, and I wasn't sure if it's coming in from the side or the front.

Anyway, I wouldn't worry too much - the engineer will sort it. For example, it might be possible for them to use the current copper to pull a draw-rope, and then pull the fibre and copper back through.

BTW I thought the filing cabinet was a 19" rack at first

Can you put your postcode and then door number into the BT Broadband Availability Checker and let us know what is says for your property on the following line

'Our records show the following FTTP network service information for these premises:'

here are the results from the checker

https://ibb.co/SRbDYTV