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:
Alexander Frederick William
Augustus Robin Gregory (Andolie Nina Patricia)
Hector Lorenzo Miles (Isla Liberty Rose & Ottilie Alice Una)
Hugo William StClair
James Thomas (Felicity)
Oscar
Robert Edward Richard (Alexander Henry Christopher)
Rupert Arthur George
Theodore Michael
Timothy Alexander (Sofia Antonia & Daniel Anthony)
Wilfred Nicholas Jeremy
William John Oakley
Girls:
Athena Mae (Lazlo)
Lara Lucinda
Mia (Thomas)
Minnie Harriet Rose (Merlin)
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.