Thanks to all of you who kindly offered help. I have tracked this down to a
Send Msg_Request_Clear to oPlateStore_DD
The grid has an index based on 4 fields. In the View, just above the grid, there are 4 forms allowing the operator to enter the positions where the grid should start and press a Button to do this. The first of the forms has:

Procedure Entering
Send Msg_Request_Clear to oPlateStore_DD
Set Value item 0 to ''
Move '' to gsFreezer
When the view is called - before anything has happened - a blank line appears in the grid, right at the top. The grid thereafter is fine. There is no 'blank record' in the database. Everything works perfectly. There is just a blank line at the top of the grid. This vanishes as soon as any activity takes place.

Although this line has no effect on anything, it just looks strange.

Anyway, now I know what's causing it I suspect I will work out how to fix it.

Kind regards,