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:
Charles William Christopher
Edward David
Frederick (Leo)
Jack Oliver
Otis Robert Ewen
Rex Lyons William (Henrietta Hester Sybil)
Robin Peter Hamilton (Phoebe & Alexander
Girls:
Amelia Star
Florence Isla
Honor (Isla Clementine, William Alexnder & Cecily Isabel (twins))
Rose Fay (Elias John)
Seraphina Blaise (Oscar Atticus)
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.