I was demand feeding 5-6 times a day right up until 12 months. How rude of Plunket to tell you off for demand feeding a 3 month old! You can not over feed an exclusively breastfed baby.
Jody was the same, started solids at 5.5 months, then at around 7 she was getting hungry more often. I added an afternoon snack, and then a morning snack soon afterwards. As long as you offer milk first until she is 8 months old then she won't overfeed. ( I was still offering boob before breakfast until about 10 months).
Sounds like you are doing really well, you want to trust your instincts but are scared of the dreaded Plunket Nurse
. You know your baby better than Plunket, nod and smile at your next appointment