Typically, I've mistakenly inserted some annotative leaders into a viewport modelspace instead of paperspace. Trying CHSPACE to bring them into PSpace makes them disappear - can't find them anywhere. Normal objects work fine.
Thanks for the reply, I checked my annotative settings and they did need updating as you suggest. Then I also realised I had Show Annotative objects-turned off -which wouldnt have helped really. All sorted! Thanks for the patience.