Please advise as it appears to be forever growing but with no outlook of an avocado ever showing. My daughter is threatening to chop it down????
Where are you and where are you growing it? Most commercial avocado trees are grown from budding or grafting a variety onto a root stock. They grow up to 20m high if planted outside in a frost free environment.
The ones you grow from a stone in an avocado from the shops will take years to get to fruiting size and are unlikely to do so as a houseplant. Have a look here for more info - https://www.rhs.org.uk/Advice/Profile?PID=957