"I have not got two" (more British English) must surely be just as correct as "I do not have two" (more trans-Atlantic English).
Lenition of "dhà" due to "eil"?
no. Dhà on it own is always lenited. Dhà loses lenition when paired with another word, rather than gaining lenition.
That explains it - have been puzzled up to now as I have memories of Dòtaman as a kid and it was always dhà in the time telling bit at the end
The computer should also accept, "I have not got two".