Hi there,
 
We have two Husky pups, one a girl @ 8 months and one male @ 6 months and both seem really small height wise. We started them on Origin twice daily and the girl got really fat because I read the guide wrong and was feeding her twice the daily amount she should have been on but we have been pretty good with the male. He had a big spurt but is now filling out and his paws are pretty small too. His parents are both big and the breeder said he should be a pretty big guy when he is finished growing.
 
It is our first experience with Huskies and our other dog a female whippet was pretty much fully grown to the max end of the scale at 21 inches by 5 months give or take. We were pretty uneducated about feeding so she lived on supermarket tins and dry until she was 2 and we got our first Husky Evie.
 
At the withers Evie is 21 1/2" @ 8 months and Sawyer is 19" @ 6 months.
Both are extremely well developed physically and incredibly strong with huge teeth, brilliant coats and really playful but we are concerned that we have done something wrong with feeding and caused them to stunt.
 
Reason I am asking is because we recently took on a 4 year old rescue male and although he is extreemly under weight because he was mistreated he stands @ 26 1/2 inches and everything about him is much bigger from the head to the paws.
 
This is Sawyer beside Bhalu
 

Both your puppies seem perfect height - remember that huskies are a medium size breed. Male can reach 53-64cm and females 51-60cm - anything within this range is ok (used cm since I noticed you are in Ireland   )
The rescue you have taken on could have a malamute in him perhaps?

haha, thanks for the metric :)No he is registered just shockingly big compared to our other two but maybe because of being underweight he is nowhere near as strong. I was struggling to see how ours could possibly be considered as 'pulling' dogs but since we put the in harnesses I have a permanently aching shoulder.

Some huskies are just bigger so that would explain your rescue's size Oh don't you worry about their strength! My girl will be starting dry sledding this April but tried her on the harness and she can definitely pull! She only weighs 17kg so I have no idea where she gets her strength from but this is how they were bred - medium, athletic, lightweight but strong.