An exact statement of the problem reveals the solution.
Having determined that I had not explained the protagonist's working methods sufficiently - or indeed, at all. I sat down and analysed each occasion in the script where she needs to use her "knack" - it's not a knack really, just an application of code debugging techniques to crimes and behaviour (that's her shtick).
An important step really, because it means I have had to move some things around. Chopped out an early scene I didn't like anyway (it pretended to move the plot but didn't really) and had to adjust the movements and behaviours of the characters in order to ensure the audience sees what the protagonist sees - though they won't interpret it the same way. Important for the genre because if the detective has information the audience doesn't have they get irritated - it's cheating.
Hopefully I shall have the script ready for external reading by the end of the week.
What's on the turntable? "The Court of Love" from the "Carmina Burana" by Carl Orff