Suddenly my whole threads view has changed - for only the last 10 years I have been seeing all the individual posts within a thread page but suddenly i see the first post only and a box below containing all the replys in an old newsgroup type style.

I dont recall changing anything, help please?

Click on the 'Options' button on the right of the thread title bar - is the Display Mode set to the 'Outline' setting? If so, reset it to the 'Standard' setting and all should be well.