The asking price for a house has no "real" significance. It's not like it's a price tag,
A starting point for a bidding war and a way to attract more interest a bit quicker.
Yes, this is a well acknowledged tactic by estate agents to draw buyers interest. It still doesn't answer why they have to use lower prices now then they were using back in April. When compared to last year there was not such a noticible dip.
I think you might be dissapointed if you're looking for absolute concrete proof of a slowdown. This will only really come out maybe 3-4 months after the market has begun to slide. If there is no pick up in sales this September or October then there's very real danger of a major slide happening.