My puppy is now 15 weeks and has never really attacked her food with gusto, although she has had lots of problems with runny diarrhoea which was diagnosed as giardia.  This has now been treated but when I feed her, she gets all excited when I'm preparing food but as soon as she gets it,  she has a little sniff, maybe a taste and then just wanders off.
She is still on her breeders diet of scrambled egg or weetabix with goats milk for breakfast, dried food for lunch and then chicken/lamb mince with rice for tea. The only meal she seems to like is the lamb and rice. However, with the breakfast, if I shove my hand in her bowl and scoop the food into the palm of my hand she will scoff it down.  Is it possible that she doesn't like to have her head in her bowl for some bizarre reason ?  Or do I just ignore her behaviour and eventually she will get hungry enough and eat properly?

I have no idea why at 15 weeks you are still continuing to feed scrambled egg and weetabix as these foods were never designed for dogs and they contain nothing that a dog cannot obtain from a more appropriate source.

I do not know what breed she is but if small she may be ok with only two meals a day, in any case I would cut out the breakfast meal and either replace with lamb and rice or the dried food.

If I was a dog I would prefer the lamb and rice and so hang out for the latter.  Dogs that are hungry do not starve themselves to death, you may be in danger of training her to be a fussy eater.

So decide on a diet, feed her and remove if she has not consumed in 10 minutes.

Hunger is very motivational.......

Totally agree with Tohme.

I'm still feeding her scrambled egg because that is what the breeder has laid down in her detailed diet sheet for the first 6 months. I apologise for not being as knowledgeable as you obviously are. 

I would subsitute the breakfast with the complete food, she will be at her most hungry then and more likely to eat it.  Try a spoonful of bio yougurt mixed in with it, that sometimes helps.  You may need to get her used to the taste first by offering a little of it on your finger for her to lick off.

If you are feeding the complete soaked, then you could mix it in with the mince for all the meals.

Just a couple of suggestions.