"Double" card
I can normally work out what happened with items of Bray-mail but this one is not so easy:
Posted on 17th Feb 1900 to Ernest Arnold with message on back.
Posted again on 21st Feb 1900, again to EWA, with first message replaced by second message.
Posted for a third time on 28th Feb 1900 to Prisoners Quarters in South Africa (Boer War).
Censored and finally sent back on 30th March 1900.
The mystery is that there are no postage stamps or charge marks "fining" the recipient for unpaid postage.
The four small holes in the corners indicate that at some point Bray had joined this back-to-back with another card forming ones of his so-called "Double Cards". It is unlikely that the first two postings were in this format since they contained messages to Arnold. Why were there no stamps or charge marks?
Maybe the other half of the "Double Card" will turn up one day and offer an explanation.