Re: 5x09 Cold Blood (Grading/Discussion) SPOILERS!!!
You assume 10 regenned in 2005. He left Rose in 2005, flew up and out. To when we don't know. Plus the regen powered TARDIS explosion could have brought the TARDIS up to 2010 then plummet it back to Earth and in time to 7 year old Amy's time.
But there's no reason to think that Ten's TARDIS travelled to 2010 before plummeting back to Earth in 1996.
"Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism and for democratic Socialism, as I understand it." - George Orwell, 1946