Clarification of probabilities

[aj2duncan]

As discussed with @OJWatson via email, thank you very much for the clarification btw, when time allows could additional details please be added to the documentation regarding the age-specific parameters.

Thanks for your work.

[OJWatson]

Sure thing - have one deadline i am stretched by over the next few days but will add this next week. Thanks again for the question and we will be working to make the documentation clearer so thanks for the question. Ta