Sometimes, because the English is so bad our members and users don't understand what is being asked! Can you believe it? [Rhetorical]

In other cases it may be that research is ongoing and the answer will appear later.

For some questions we feel it is best find an expert to answer for us and this can take time, we hope eventually to answer all questions.

We do relish tricky questions and conundrums such as 'How long is a piece of string?', but reserve the right to give slightly cheeky answers....

To set the record straight, most of the questions do have answers. There are around three and a half thousand questions and only around one hundred are unanswered, many of the questions have more than one answer.