I wrote a much longer version of this post but realised that it duplicated a lot of the original document in the first post of this thread. I’d highly recommend reading this as our policies have been built on it.
Legal and preferred names can be different for a number of reasons though and we would make a judgement call as to if it is appropriate. Having helped a large number of people through these, it is incredibly rare that I have to deny this.
One of the major places where we are required to send your legal name is unfortunately outbound bank transfers. There is a ticket open to add a warning about this in a future app update but to change this, you would unfortunately have to go through the deed poll and ID update process. A future update to the service currently in development will automatically drop middle names though (but hopefully without dropping parts of double-barrel surnames) as this is by far the most common feedback we get here.
For card emboss names, we have a stricter set of rules due to the restricted length of these. There are almost too many to list here but get in touch with support if you’re unhappy with the options or what our name shortening service chose, we take the feedback very seriously and use it to improve that service for others.
In general, we don’t like the word “nickname” and stick to the above terminology of legal and preferred names internally. We also don’t like to say that names are “real” or “fake” due to the freedom of self-identity in the UK as described.