Far be it for me to defend UKAD, especially when it comes to Athletics, but the point they make is absolutely correct; any request to retest samples has to follow due process as laid out in the rules of the sport. To do otherwise completely undermines the anti-doping process.
Move along, nothing to see here...
https://www.theguardian.com/sport/2020/jan/20/jessica-judd-ukad-mo-farah-samples