Oooh! Thanks talesofthesevenssea s..I am a bit excited now.
The carving at the top of each chair has inconsistencies between each one, lines a little longer or wider, different depths carved out.
The stippling appears to have been made using a tool with several 'pins', so whilst they appear to be in rows, they are worked around the raised part of the carving and differ slightly on each chair.
When planning to paint the chairs, this was the area I had reservations about and thought I would paint around the carving, leaving it as is.