Then there are the other eleven. Funding an entire collection requires deep pockets, and collecting the Dirty Dozen – especially if you want them in original condition – is not without its pitfalls. Due to the extreme conditions they were subjected to, many of them were repaired and restored at some point during their lifetime. And that meant being sent back to the Corps of Royal Electrical & Mechanical Engineers (R.E.M.E), which dealt with all mechanical equipment in need of maintenance or repair, including watches worn by military personnel.

Of course, the Corps had little interest in preserving the originality of the watches that came back. Their primary concern was to get them back in the field as quickly as possible, and they found it much more practical and time efficient to restore watches using MoD replacement parts of lower quality and in some cases, with parts from other models. Mistakes were made, especially when changing case backs. And then there's what happened after the war. In the 1960s, dials containing radium and promethium were replaced by non-radioactive dials (the Longines and the IWC in the Watches of Knightsbridge are both examples of this practice).

Because of this, collectors should tread carefully when acquiring these watches online or through auctions, if the originality of the piece is their primary concern.

Besides the Grana, the most elusive W.W.Ws are those which returned, albeit briefly, to MoD at the end of the war in Europe. Those that could be saved, or did not need saving, were sold to other Allied forces still engaged on other fronts, such as the Pakistani Military, the Dutch Military and the Indonesian military. These have a fourth line of engraving, identifying the watches’ new owners.