Tomb alignment was a standard element in these volumes, indeed, each tomb class has a composite diagram showing the alignment of every tomb in the volume. So we would have greater than normal faith in the accuracy.

This is really an excellent series of books, with first rate descriptions and measurements, the plans of the tombs are very detailed, in many cases they are large fold-out jobs. We enquired at Hertitage Ireland which took over from Duchas, but they knew nothing of the series, so it looks as though it has ended with Vol.6 :O(

Maggie & Keith