I'm not sure my words will be too re-assuring as you have heard them before! As above, only the PSTN is switching off. Some people will say that FTTC is ending, it is partially true. GEA-FTTC will cease as a product, this product needs a PSTN (using the WLR3 product) to work. However, Openreach have brought in SOGEA (Single Order Generic Ethernet Access) to fix this, its exactly the same FTTC line but without a PSTN/WLR service. Your provider can switch you from GEA-FTTC to SOGEA as Openreach have finally released a process for it. The only issue is that it currently costs. I was at BT Tower last week with Openreach and raised how it was ridiculous that CPs/End Users should need to pay to allow Openreach to close the PSTN network, hopefully they will see wisdom soon but in the meantime, don't worry about it, your FTTC will keep working. You shouldnt even notice the switch to SOGEA as its just a removal of jumpers. We are going to do a test migration soon at a site where FTTC is the backup. Happy to let you know how it goes.
EDIT TO ADD: It's worth adding that this isn't the case everywhere. There is a stop-sell in some places, for you for example Tadcaster, where, if FTTP is available you at some point will no longer be able to buy FTTC. But Openreach are rolling out a 4 port FTTP OLT so it will be easier to have multiple lines on FTTP without a fibre for each.