it's just that trading for me is quite an instinctive thing, you just get a feel for the markets having watched them for many years, and i feel they have changed quite alot recently.
i know thats not very specific, but i dont have any data to prove or disprove anything,
but as euler confirmed fill rates are slower so im not going mad after all

I wouldn't be at all suprised if xm had been cranked up a notch or that betfair have found new ways to profit from the markets, they are just a bookmaker at the end of the day so they can do almost what they want with regard to matching bets ect.
There are a million ways they could be profiting.