Below is a round-up of the birth announcements from British newspapers. Sources include a national paper (The Telegraph, The Times) and a broad range of local newspapers from across England, Wales, Scotland and Northern Ireland.
Sibling names are in brackets. No official surnames are included; any name ending in a surname is actually a middle name.
Boys:
Alec Theo Gabriel
Alexander Frederick
Alfred Simon Edward
Arlo Frank Rizal (Jack Alexander Eko)
Atticus Hamilton
Auden James Dillon
Barnaby Francis David (Calliope Margaret Evelyn)
Frederick Oscar Peter (William Nugent Alexander)
Jaxon James
Jonathan Francis Kofi
Mason Hugo (Teddy Hunter)
Miles James Leopold
Mobius Charles Timothy (Darcie)
Robin Elis (Rupert Lawrence)
Rory Arlo
Sebastien Emmett
Theodore Albert Edward
William Caley (Thomas Pippin)
Girls:
Clementine Summer (Henry)
Delphine Eulalia Louisa
Elsebeth Margaret (Claudia & Gabriel)
Emilia Anna Florence
Harriette Rose
Josephine Eliza Ducie (Martha Katherine Victoria)
Lily Fenella
Mia Elizabeth
Millicent Pearl
Ottilie Flower Vandezee
Twins:
Annabelle Victoria & Zara Alexandra
Augusta Patience & Constantia Daphne
I cross-reference older BAs to find the full names of the siblings, however often they are missing (especially the eldest siblings, or for half-siblings) which explains why you will sometimes see something like: George Henry (Lucy, Emma & Jack Arthur). "Lucy" and "Emma" may well have middle names as well; I simply cannot find them online.