I had a landline number with BT for the last 21 years. Last month I ditched BT (Plusnet) and migrated my landline number to Sipgate.
I now have Virgin Media broadband only (no Hyperoptic round my way) and it means I’m no longer paying through the nose for the dinosaur technology that is twisted-pair copper.
Sipgate works well and I retain my landline number that I’ve had for years.
I’ve actually been using Sipgate and Gradwell for a number of years. I also use a client on my iPhone to make/recieve calls with landline numbers.