Note gratefully received from Jane Lawson of Woolwich, London, 5 January 2023:

‘I expect you are familiar with the practice of chalking on the door on [5 January] the eve of Epiphany. Christus Mansionem Benedicat.  Christ Bless this House, and also the initials of the magi – Caspar, Melchior and Balthazar.  Found all over Europe and in many Catholic and Anglican houses and churches here.  My  [Catholic] French mother used to put rosemary [Salvia rosmarinus, Rosmarinus officinalis] and rue [Ruta graveolens] on the door, but I’m laid low with a virus, so can’t gather any.’

At entrance to St Mary’s (Anglican) church, Balham High Road, London Borough of Wandsworth, 16 February 2023:

At exit to Wakefield Cathedral, West Yorkshire, 18 February 2023:

Updated 20 February 2023.