"... and some of the plumbing fittings are modern"
I found that the
oil system priming is missing. I'm not too familar with such system, but a banjo bolt without hole for example, can't be right.
BUT, in Pur Sang's defense: We don't know if this very car was from them or any of the sattelite producers that possibly mushroomed nearby. Sort of like what happens in Poland, near Kirkham where you can buy Kirkham replicas.
Don't ask me where, but I have seen alu Cobras from Poland advertised in Germany which were not Kirkham's.
Maybe there aren't any Pus Sang Bugatti Replica Replicas yet, but I have seen Maserati A6GCS from Uruguay, with a motor from Pur Sang (as advertised).
No real secrets here, just saying.