I've had some handy photos sent in showing the radishes at different stages, so this is what you should be looking out for. The plants do seem to be being quite variable in how they grow and how fast they produce a flower spike - I am having a think about modifications to the protocol that can be done if yours are being uncooperative, and will get back to the list this week with my ideas.

For now though, thank you Rita, and here are what the radishes should eventually be showing! Click on the pictures to zoom in.