I think how long it takes varies from assessment to assessment... I went to the one in London on 29th April and the girls and I did not get a reply till after one month....we got the same email that maquillage is talking about..... then a week ago I finally got the call and an email with my contract etc.
I checked my email all the time too but eventually gave up cos it took sooooo long..... and it wasnt supposed to..... but in the end all worth it