yabu,
it is not that 8 pm is very late, but if it is late enough for your neigbour to be unhappy then it too late in this instance,
so much so that instead of grumbling to herself for 30 mins she called round and asked you to stop,
imho you should respect that,
i have to say that i think knocking bricks from a fire place is noisy, for you and for her,
i know it is a messy job, and if you work all week it is an arse to do at the weekend, but if you hardly ever do diy then it wouldnt be the end of the world if you took the dcs to the park/shops/cafe for 2 hours and dh did the work while noone was home,
even better would be to ask/tell/say sorry to your neigbours in advance when works like this need doing,
i do, and they do, no problem all round,
that and it is the christmas holidays, even more reason for them to be relaxing in peace