hay dig..
Mate I was in the same boat as you, 6.4 and 80kg! I started training just over two years ago and for the first 6 months I didnt gain any weight actually got lighter :( since then i looked into my diet cause I was eating a very similar food balance as you were.
I now consume around 3500 to 4000 cals a day with atleast 200g of protein every day and I have hit 97kg so I have gained around 17kg in just over 18month
for the second part of my first year I added 3 weight gaining shakes into my diet one in morning one after work out and one before bed gained 10kg in 6 months...
Now I have droppped them for whey and and eat
meal 1 oats banana with honey and skim milk plus 2-4 eggs with two toast
meal 2 60g whey protein shake
meal 3 chicken and rice
meal 4 chicken and rice
meal 5 meal replacement shake with 30g protein
meal 6 60g whey protein after work out
meal 7 500g steak with veg and potatoe
meal 8 4 eggs but this is only sometimes if i feel up to it
(if i cant be bothered with this i have a weight gain shake)
give it a go champ I guarantee you gain weight, cause i never could before i started on this.
Anyways all the best
lets us no how you go