I think you are missing the point. Your internal wiring is your responsibility, nothing to do with BT.
If your appointment is with a BT/Qube "engineer" under Halo, be aware that their skill set seems to extend to wearing a polo shirt with the embroidered logo at the front.
What happened after you first raised this in February?
That’s why I asked initially why the tech was visiting, you stated that after the router shift the speed was consistently just under 100Mb , which suggested to me that this is worse than when connected at the original location .
If the speed is below the minimum guaranteed , which I think is around 700Mb on a 900Mb service then obviously if this is apparent when the tech visits again at the original location of the router , then that’s fine , no worries about charging
….FWIW , if the speed is below minimum at the original location then it was always nonsense for the tech to think by incorporating some third party wiring that it was going to fix the problem , the tech should have known the underlying issue would still be there….but TBH , your post focused on the speed after the router shift , not before , hence the understandable suspicion on the cable used to relocate the router.
To be fair to iniltous, I think he is just trying to alert you to the fact that if it is your internal wiring, it’s not an OR call out and they will charge you for wasting their time. Any internal wiring is the property owner’s responsibility.
Under the circumstances the first thing to do is move the router back next to the ONT and check the speeds again. If that fixes the problem then it is definitely your internal wiring and OR will not fix it. If the problem persists then it is an external fault and the OR call is appropriate.
It's not something you can do, but depending on factors like availability of a power point, suitable route for the fibre optic etc., yes it is doable...but it will be pricy again. You'd need to get BT to book it through OR.