Have noticed lately that if you are searching, for example a birth in 1876 Stepney, if you put in the "County" search box Middlesex then it will only return results from the places that are currently in Middlesex, for example Brentford. So although the person was born in Middlesex you now have to put London as the county instead to get a result.
Thanks for that info, some of my wife's ancestors were from Middlesex, I'm not currently continuing researching her side but no doubt I'll go back to it sometime.