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.
Boys:
Alfred Oliver John (Lila)
Arthur
Bertie Antonio Michael
Casey Ray (Ebony Iris)
Patrick Sonny (Conrad & Oscar)
Ralph Valantine (Rex Lysander & Felix Rufus)
Sebastian George (Amelia Rose & Max Alexander William)
Girls:
Alice Constance
Antigone Dusty Rose (Theodora "Teddy" Kate & Primrose "Posy" Ophelia)
Delphine Esther Violet
Francesca Rosalie (Matilda Sitelle)
Matilda Rose Linton
Twins:
Harper & Olivia
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.