Is there a function/formula I can put into a series of cells which can look
at a list (with repeat entries) and simply return the unique one.

E.g.

Tomato
Tomato
Banana
Tomato
Pear
Banana
Apple
Pear
Apple
Tomato

Would be displayed as

Tomato
Banana
Pear
Apple

Then I can use Validation on this 'filtered' selection to create a drop down
selection box.