See his interview to the BBC at:
A key article is probably the one he wrote that says that athlete's can avoid the biological passport - the new ray of hope for anti blood doping.
European Journal of Applied Physiology (2011) 111(9):2307-14.
"Current markers of the Athlete Blood Passport do not flag microdose EPO doping".Ashenden M, Gough CE, Garnham A, Gore CJ, Sharpe K.
It looks like Ashenden thinks the anti doping agencies are not comfortable with these sort of articles being written - in fact they are proposing that exports must stay silent now and for eight years after they have served on a panel. This is a pretty impossible position for an academic scientist to be put in.
As I say in my book about the passport:
"If the system is going to work in the future and not be continually mired in the courts it seems to me that complete transparency and openness is necessary for the passports, even at the risk of allowing the dopers to have a better idea of how to avoid suspicion. Why are the cycling authorities wary of such openness? Well there is evidence from the confessions of the cyclist Floyd Landis that cyclists have modified their EPO doping regime in response to the introduction of passports. The trick to fool the current biological passport seems to be to dope little and often, rather than in the one large dose that leads to suspicious spikes in blood parameters. The war continues."
As a scientist my sympathy is with Ashenden (whose paper I should have cited in my book by the way - apologies!). If we are not going to go the police state route and have undercover cops infiltrating athlete training camps, we are going to have to succeed by openness so the court decisions are not only effective, but seen by everyone to be fair.