Thanks for this, Ronan.
However, returning 5 rows isn't the correct answer because there are two records which have the same prize amount. The answer should display 6 rows, and I know LIMIT 6 would do that, but is there a statement that will return the 5 highest prizes without knowing how many records this covers? Eg, what if there were 25 records which all fall into the top 5 prize amounts?
In other words, do I need to look at the data to work out how many records should be returned in my query before being able to create this query, or can I create a query which will do it all for me?