Please can someone help me identify this?
This is a Chaenomeles speciosa, commonly known as flowering or Chinese quince, sometimes also as Japanese quince (but not to be confused with the smaller shrub  C. japonica, also known as Maule's quince).

It is edible, but very sour (lots of vitamin C!), very hard and often slightly bitter. Culinary uses are similar to regular quinces (Cydonia oblonga), but due to the high pectin content they are especially suited alone or mixed with low-pectin fruit for jams and jellies.

The plant itself is - at least in the western world - typically planted for the showy flowers as ornamental hedge (C. japonica is smaller and often planted as solitaire), not primarily for fruit. In fact, many gardeners don't realize that chaenomeles are edible.

The fruit in your picture are far from ripe, they need at least another two months and will turn yellow and fragrant with dark kernels. They remain hard and if picked before the first frost and can be stored for months. Harvesting after the first frost gives you slightly softer fruit with shorter shelf life, but even better aroma as some of the bitter components are destroyed.