It took some years, but eventually the gender neutral social title Mx became a title used alongside Mr Mrs Miss and the rarely used Master and is now included in the Oxford Dictionary.
A social title is not an integral part of an individual’s name and therefore there is no need to get a deed poll.
Remainers could use Rmr as a gender neutral social title before our names to denote Remainer. There may be resistance, as there was with Mx, but in many instances eg some online forms, you can use whatever social title you want to or add Rmr under Other.
If you want to sign yourself as Rmr Joe Public on an email or letter, there’s nothing illegal about that and you haven’t changed your name.
When it comes to banks, they may not recognise Rmr, but it’s a question of numbers. Until they do, you might have to continue with your current social title for banking transactions.
Rmr is an option.