Yeah but the American series shows a few episodes then takes a long break, then shows some more, thent akes a break. Also the previews on the site for forthcoming episodes are episodes due to be shown her shortly, also.
Basically we'll be one ep behind the US. Sun April 8 sees the season pick up in the US from ep 17, with ep 18 airing the following week right until the end of the season which in the US will be on May 20.
On Wed April 4, the UK air ep 16 on the E4 'first look' and ep 17 on 'first look' the week after (11th). The finale over here will air presumably on May 23 with a double bill on C4.
The reason Lost took such a long break was because they were making sure that had enough weeks in hand over in the US so they could run it every week until the end of the season. Housewives didn't have a break because it started later (24th Sept 2006 over in the US and Jan 3rd over here).