When choosing a suit for kids it's important to remember that a suit that's too big won't keep them warm and a suit that's too small will be uncomfortable, so don't try to choose with a view to making the suit last two years. It will be too big in the first year and too small in the second. 

In the event that you're not entirely happy with the fit of the suit it can be exchanged provided that it has not been used (please note that the cost of postage is not refundable).