The fifth hint for Challenge 10A
If we think this is a Hill cipher and that the names JODIE and HARRY are likely to appear at the start or the finish of the text, then we might see the pairs
in those positions. Assuming that we are using the convention A->0, B->1, C-> 2 and so on this would give us a series of equations that might allow us to work out the Hill cipher matrix. Take a look at Unit 88 in Madness’s book to see how to use that information.