What exactly is your business - selling designs or selling clothes?
Do you understand much about fashion retailing? - the margins are incredibly large between the raw cost of fabric plus sweat shop labour and full selling price (typically 600%) but the potential losses are massive as well - this is why clothing retailers are forever having 'sales' - they still make a profit agaisnt direct costs. Guessing the ratio of sizes to be manufactured is a nightmare.
Large retailers source their own designs, source their own fabric designs from Bangladesh (amongst other places), transfer the fabric to Far East sweat shops, then ship products by sea in containers (it takes 6 weeks). Presumably this is not the markey you are in?
Now go back to the first question and research how and where you think these designs are going to be sold.
If you want just a few dozen as samples made up, look in the yellow pages around Leicester - there's probably a few vestiges of the UK clothing industry remaining up there.