That's rubbish service jane but don't let it put you off online shopping generally.
I get things from Boden, Uniqlo and Toast and the stuff usually comes within a couple of days at the most.
You can try stuff on with the things you want it to go with, keep it for a few days until you're sure you're happy with it.
If you have to send it back and pay postage, so what? It's probably less than the cost of driving to the shops and paying to park your car. 