instead of producing long straight white radishes they are long twisted ones. Any idea what might have caused this?
This corkscrewing / bending happens with many plants when the growing tip touches an obstruction.
In this case the tap root may have touched a stone and then bent around it thus creating the start of the corkscrew shape.
It is common sight with other root vegetables such as Parsnips,Carrots and potatoes to a certain degree.
A similar thing happens with sweet peas and runner beans e.g when the growing tip of a sweet pea touches a leaf or stem it often results in a bent stem. With runner beans a similar thing happens when the young bean touches a leaf or stem this can result in a bent bean.
Regarding the blue rings I am not sure what causes this but I don't think it is connected with club root At a guess I think it might be down to irregular moisture take up, but as I say this is only a guess.