Board Thread:The Panopticon/@comment-9435571-20140728160616/@comment-188432-20140729015319

They're different because there's no explicit connection between them. The two (or maybe even four) Mark Sevens are in different organisations, different millennia (not even centuries) and have quite a different set of co-workers/friends. Moreover, the prose version (or possibly even versions) is not known to his co-workers as an android. That's not the case in The Destroyers, and it's a big distinction. It indicates that the android is of sufficiently advanced design that he/it could totally pass as human.

In a case like this where you have a fairly generic name, but significantly different settings and character traits, it's up to the person asserting they're the same to find positive links. You have to prove how they're not different characters, using the text of the adventures in which they appeared. In other words, deductive reasoning ain't enough.

Think of it this way. Dr. Who is not the same as the First Doctor despite the fact that they both have white hair and granddaughters named Susan, and are both occasionally referred to as "Dr. Who", and they both went to Skaro to fight the Daleks. Why? Because generally there's no narrative connection between the two, other than a vague similarity of events. Barbara can't be both the Doctor's granddaughter and Susan's unrelated schoolteacher. That's just obviously too big a difference.

Indeed, K9 Mark II may look like K9 Mark I, may be played by the same actor, may have the same incarnation of the Doctor as his master, and may be thought of by the general public as the same character. But we know they're not the same character because we've seen the last scene of The Invasion of Time. We know there are extenuating facts which make an otherwise apparently similar character quite different.

In the same way, there is more than enough in the written stories featuring Mark Seven to make us believe he is likely different from the Big Finish version. I'd even go so far as to say that there could be enough of a difference between the 60s Dalek Annuals version and the 70s Dalek Annuals version to say that there are two prose Sevens, and possibly enough difference between the Nation version of The Destroyers Seven and Briggs' version of The Destroyers Seven to call those different.