I have a resolution to this problem which I'm still not sure that I believe and certainly don't understand why it works:
After repeatedly halving the rows selected from the failing half I ended up, eventually, with no error. I then started recombining the splits in combinations that looked likely to work until I got two relatively large groups of data that both worked. One group contains 305 items from the main table which is 15,757 rows in the view while the other group has 80 items returning 12,490 rows from the view. It's no problem to combine the two reports so many thanks to Bill & Larry for putting me on the right track. Regards, Alastair.
