I've found Croftindacker on a map surveyed in 1870.
However the same spot is clearly marked on a map surveyed in 1926-1927 and on later maps as Croftintaggart.
See attachment and
https://www.geograph.org.uk/gridref/NJ1537, which shows where the ruins are and even has a photograph.
I would put the stress on the first a, making it Croft-n-TAG-rt, but am willing to be corrected. It would sound very odd if any other syllable were to be stressed.
The practical difficulty is that since that second map was surveyed in 1926-1927 the croft, whatever its name, has been swallowed up in a forest plantation. So it may not be easy to find someone who remembers hearing it spoken of.