To pay off the current house would cost me £50k, then spend half a million to buy a huge house to live in, along with all the gadgets, furniture, and solid wood you could need. After that spend 4x100k to buy four more houses.
That leaves £2 million to live off, plus the rental income of five properties, and a spare 100k to cover emergency repairs, and furnishings for the rental places.
If I won/earned/received £2 million I would probably need to keep working, unless investments did exceptionally well, but £3 would be sufficient for myself and partner.