All UKA race results and parkruns from recent years should be on powerof10, however you only appear on the Athlete search results if you have achieved one of the 'standard' times that Stevie G listed, or if you specifically request to be included in the Athlete search results.
Regardless of whether you appear in the Athlete search results, if you have registered on either runbritainrankings or powerof10 then your data will be on both waiting for you to log in to see it. They share the same user database, so for example if you know your athleteid from the URL of your runbritainrankings profile then you can just paste it onto the end of the equivalent powerof10 URL and voila, bookmarkable link with no need to log in:
http://www.thepowerof10.info/athletes/profile.aspx?athleteid=