I like that you included photos of the printed t-shirts, also I like that you're using a printer with no web presence so we can't go straight to the supplier, hah.

A cute idea that might help people to spread their shirts: If someone creates a shirt (let's say I'm miley cyrus and I make one for my fans, "I <3 @mileycyrus") and it gets x (5?) sales they get a free copy of the t-shirt. That would give users an incentive to share their creation with their Facebook friends and Twitter followers.

The way you described the t-shirts makes them sound quite appealing so I figure I'll order one, no idea what to put on it though... :( maybe "I just wanted a t-shirt".

oh also I assume "handmade in London" refers to the business; but with t-shirts it would read as if you're saying the t-shirts are handmade in London, which isn't true.