Mhairi's was from our local baby boutique, Cradle Care.
It was a Sarah Louise gown, and they have some lovely boy stuff too. "Sunny" Greenock might be a bit far for you to travel though! Or you could make a say of it and Mhairi and I will take you and Aiden out for lunch!
Or there is a boutique in Paisley, called Rascals that do Sarah Louise too. I'll see if I can find a stockist nearer you!