If you asked them for FTTC and they came and installed something else then I'd suggest that isn't really your fault. I'd just proceed with ignorance and assume BT are doing what you asked them to do. I very much doubt anyone will ever notice if you've had FTTC/FTTP installed and you'll be fine to continue as-is providing they aren't digging huge trenches in your garden or removing walls to do it. Just get anything external put in a not-so-obvious place.
Sounds like you may be making a mountain out of a mole hill, if your address is shown as a two stage install , the Openreach person provides the fibre to the outside wall and provides a small termination point, ( if that’s where the existing copper pair underground service appears ) , the second part is OR run another cable to the inside of the property and fit the ONT, the reason for the two stages, is in case getting the fibre cable to the house hits problems , like the duct blocked , or the existing copper cable isn’t ducted but buried direct in the ground and no duct actually exists, this give OR time to resolve these issues , before you get a proper appointment for the ONT to be fitted.
This is a very common process on relatively new property’s that are ducted from the roadside, if you have a listed building it likely not a particularly recently built property , so who knows what type of existing copper service is provided .
BT ( as far as I know ) don’t sell FTTC where FTTP is also available , but not all providers have made this choice, in fact some providers don’t ‘sell’ FTTP at all, but do sell ADSL and or FTTC , so if it’s that much of a concern you could simply order service from someone else that don’t offer FTTP....but as already stated , this is hardly something that’s going to get the local government planning officer concerned