Former Godolphin trainer Mahmood Al Zarooni has instructed his solicitors to investigate the soundness of the eight-year ban imposed on him by the British Horseracing Authority.

Al Zarooni was found guilty of administering anabolic steroids to 15 horses in his care at a BHA hearing three years ago and admitted to all breaches of the rules.

His latest move comes after trainer Jim Best's guilty verdict relating to non-trier charges was quashed after it emerged the chairman of the disciplinary panel, solicitor Matthew Lohn, was engaged by the BHA on other matters, giving rise to claims of an appearance of bias in favour of the governing body.

The BHA said that while there was "no suggestion of any actual bias" in the case, the non-disclosure of Lohn's other work "created an appearance of bias", and a re-hearing was announced.

Lohn also chaired Al Zarooni's disciplinary panel hearing in April 2013.

The disgraced former trainer's solicitor Harry Stewart-Moore, who also represents Best, confirmed to Press Association Sport that Al Zarooni had asked him to look into his case.

However, the BHA's media manager Robin Mounsey revealed that Lohn started advising the ruling body on other matters from October 2013, six months after Al Zarooni's hearing.

"The BHA recently announced that it has written to a number of individuals who were party to one of seven disciplinary cases where there might be grounds to claim an appearance of bias (although no suggestion of actual bias) in the panel hearing those cases," Mounsey said.

"These were cases in which Matthew Lohn sat as a member of the BHA's disciplinary panel following his instruction by the BHA in October 2013."