Looking at the wiki, it’s “available to subscribers of Big Finish’s main Doctor Who range whose subscription included Blood on Santa’s Claw and Other Stories.”
So, you’d want to go to Subscriptions - Big Finish and select a 6-month download subscription for #201 onwards and then select a starting title that allows the right story.
The subscriber short trips are so annoying because if I want to complete Romana I’ll have to buy six main range stories I don’t really want just to get my 40-minute story
Does anyone know how to listen to The Doctor’s First XI? On tardis wiki it says subscribers to Architects of History get it but when I looked to subscribe to 6 MR stories including that one the only bonus story with them was An Earthly Child. I don’t want to risk spending money on a subscription if I’m not 100% certain I’ll get this story as well, since it’s all digital only and I absolutely despise paying for non-physical media.
Sadly I don’t but if I am not mistaken @Jae, so they might be able to help you with it! (Sorry for tagging you, Jae, hope you don’t mind (in case if you do, let me know for the Future!) !)
Also, yeah would be probably quite helpful to pin this one so it’s easier to find as well!
Physically, you can look for second hand copies (may be expensive), but they are often included in the Titan comic collections, so if you know what ones you’re looking for, I can always help you find the collection.