The 80 serial number is engraved on the exterior case back, as I understand was normal. It is also printed on the international warranty card and on the chronometer certificate together with the reference 15024000 on both. The warranty has the printed name and address of the then Changi Airport jeweler (sic) and the date space has hand-written "22 Dec 2003". The warranty also has 5230 printed on it, which I assume was the retailer's Omega reference. The pictograms card only shows the reference and calibre number 1120 and also shows the instructions edition as "02 3". The instruction booklet shows the copyright printing reference "10/03 - 250000 - 03090840". On purchase in 2015 the watch showed absolutely no evidence of having been worn, let alone requiring a new movement. None of this makes sense to me. Perhaps I should write to Omega and ask but will I receive a reply?
Best
Clive