Dear what2
I will write a proper introduction in due time, but while enjoying "British Humor" in another sub-forum I ran into your post (I like IWC Mark XV, XVI and XVII also) and I decided to join this forum.
Make sure that you have the proper "Perfect Clones" URL as there are many fakes.
Please note that in the URL found by you of the IWC Mark XV there is no endorsement of www.rwgforum.net nor any of the other ones, mmm...
I believe the correct one is: (as of Nov. 18, 2013, they change often)
www.p-cls.com/iw10020-mark-black-dial-swiss-28242-p-1994.html (still obtainable with ETA 2824-2 ?)
Perhaps an Admin or Mod could verify this URL duality.
Also note the 38mm x 9mm in www.fliegeruhr.ch/mark_xv.htm instead of 39x12 of the replica you selected.
Regarding accuracy, again as of today, I believe Puretime has the best XVI with A2892 and Kuvarsit the best XVI price/quality ratio with A2813, both "version 2" or "new KW"
Best regards, Harold