Ambassador, British Airways; FlyerTalk Posting Legend
Join Date: Apr 2012
Location: Leeds, UK
Programs: BA GGL/CCR, GfL, HH Diamond
Posts: 43,196
Whilst understanding the desire to provide a surprise, I am not clear why sending an email to your wife about a booking she is on with you could be considered as a breach of GDPR? Presumably she also received and email when it was originally booked prior to your recent upgrade?
One might even argue that BA has a duty to send an email to a passenger whose booking has been changed.