Actor Allusion: The Doctor is referred to as a "ponce" a couple times. Particularly notable in The Fall of Yquatine, in which it seems to happen just for the sake of having him be called a ponce, possibly demonstrating the enduring popularity of Withnail and I amongst drunken humans throughout time and space.
The Doctor hurried through the marketplace, dodging people and beings, haring round corners, knocking over a pallet of fruit, stopping to apologise and then having to run away from the irate vendor, falling over a small child who burst out crying, standing on the toe of a very old and irate Draconian, getting called a ponce by a group of drunken humans, generally causing total chaos wherever he went, but getting absolutely nowhere in ﬁnding Compassion. (p. 30-31)
Alternately, Doctor Who being the sort of series it is, you could consider them something less than altogether Jossed. Zagreus suggests that the EDAs exist in an alternate universe to the one in which the Big Finish audios and The Night of the Doctor take place in. So it's all happening in the same multiverse. And The Company of Friends: Mary's Story contains references to companions from multiple continuities, including Compassion.
Keep Circulating the Tapes: The EDAs are long since out of print. If you're looking for physical copies of the books, prepare to be on eBay. All the novels are available to download for free somewhere out there as PDFs
Although the BBC reissued a crop of a few of them at the end of August 2011.
What Could Have Been: The villains from the second major arc of the series, Sabbath's allies, were originally meant to be the Daleks, reappearing after 52 books and 6 years absence. The Council of Eight was a last minute replacement, meaning some of the clues as to their identity ended being a bit misleading.