@sod - ok - the rebuild you suggested seems to have partially worked - up to 91 pages of replies - but it has now stopped. I logged the issue with @help - meanwhile - what I do have is clearly working - marvellous work - thank you...

One enhancement request for the future - filter to search 'posts', 'replies' and 'posts and replies'.

I also note that despite creating a page to be added to the menu ... it isn't showing up ... that might be latency from micro.blog - but let's see what happens by tomorrow.