I am thinking of upgrading to fibre. I have three questions.
Will I have a break in broadband service, and if so, how long will it be?
Do I need an engineer to come into the house ?
Do I need a new router ?
There should be very minimal downtime in normal circumstances, an engineer just needs to change a cable or two in the street boxes.
No home visit is necessary.
Maybe. Depending on what you currently have. Some TT routers can handle both normal broadband and fibre. What is your current model number ?