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:
Arthur W. R (sic)
Augustus Donal "Gus"
Charlie Brian David (Ashleigh, Thomas, Peter, Danny, Lucy & Jack)
Edward Thomas Michael (Hugh Frederick Arthur)
Henry Frederic James
Henry John Peter
Jack George (Issy & Tom)
Jonah Jude (Esther)
Leonardos Alfred "Leo"
Oliver Edward Rory (Henry James Johnny)
Rupert Bode Peveril
Theodore William
Tyler Reggie William
Girls:
Alexandra Maggie
Alice Araminta Clover (Poppy)
Charlotte Louise
Daphne Susanna Pica (Athena Rosemary Moire)
Kitty Elizabeth Iris
Lydia Charlotte (Bertie)
Tabitha Willow
Winifred Diana Caroline "Winnie"
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.