It's complicated - best thing to do is phone up Medway and ask for raw scores.
There is a link under '11plusadvice' (above - next to 'Home'). Perhaps you can find the information you are seeking there.
Yes. 75 is low - All children who sat the test
would have a standardised score between 70 and 140. It doesn't allow for second guessing the raw scores. Maybe everyone scored over half marks...
Phone up admissions and ask.
Edited to add: http://www.elevenplusexams.co.uk/advice ... xplanation
Here's the link.