OK, so you're guess is as good as ours as to what exact day the FarmVille English Countryside expansion will launch -- all we know at this point is that it's expected to arrive this week, as per this EC Facebook fan page update from last week:
FarmVille English Countryside will be launching NEXT WEEK, so make sure you're ready for travel! If you are not level 20, start leveling up today (Hint: Strawberries and Aloe Vera are especially great for gaining XP!) Make sure to send your friends special delivery gifts so their gift boxes are full when they land in the English Countryside. Cheers!