My lad now weighs 34kg (was once 44!! I am ashamed to say) and is on Burns.  I have reduced his intake to get a little bit more off him because summer coming up but I am concerned that he is not having enough now for the amount of exercise he does.  He currently gets about 250- 300g per day split into 3 meals.

He has 3 walks a day (about 2 hours in total) and I do training with him almost every night.

He is sooooooooo hungry at the moment tho (I know, I know, I know - he's a lab blah blah etc) but I just dont want him to get too low on food and want to balance out his intake of food to his exercise if you know what I mean.

Spoke to "nutritionist" at Burns and she sounded like she had been pulled off the street and put on a phone to "advise"!

Does this amount sound about right for him for the amount of exercise he does??

Cheers guys.

How old is your boy? Just ask because you may find it works better to split the meals into 2 rather than 3 unless he is under 6 months old.
I don't weigh my food out but feed by eye, have just fed them all and have used a standard petfood measured cup to see, the golden dogs who weigh 32 and 34kg have a full cup, the golden bitches who eigh between 26kg to 30kg have just under a cup, they are fed twice a day. Mine have the same amount of excercise as yours but a free running all the time.
Does your boy look good on this amount of food ie: is he in good hard condition and not roly poly and can you see a waist? If so i would say that the amount sounds about right. I would go by what the dog looks like rather than what they tell you to give on the packet and how true that labradors are notoriously 'hungry' dogs that would eat till they pop given half the chance.
Hope this helps.

Both mine are fed on burns, they both weigh around 30kg and have 300g per day split into two meals with a little added raw meat.  both get about 2 hours free running per day, plus agility training 3 times a week. If you are worried he is not getting enough why not put him on burns high oats, that way you can get the extra pounds off and you wont have to decrease the amount fed, this is what I did with Alfie.

Its a shame you didnt have more luck with the burns nutritionists, ive always found them really helpful.