Did receive the RT today, so the postman is safe!!
Crossword completed but I did find myself "knowing" the answers and then having to find the reason why - if that makes sense! It took some time to sort out 15a & 16a. Different use of language e.g one out, to create final answer.
With 18a, the use of the word "unexpected" was, I thought, misleading and led to a very wordy clue.
For 24a think 2 words; one for a "criminal" fiddle linked with a technical term used in physics to describe the state of solid items.