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 William (Thomas)
Auben Brian
Bo Charles Christiaan
Fitzgerald Byron (Celeste Marie)
Francis Railton Erskine (Constance Elizabeth)
Freddie (Max)
Henry Roger John
Parker Henry Nickolas (Serenna Joyce & Cassia Jayne)
Percy William Oliver
Girls:
Antonia Nancy Peggy (Theodora Elizabeth Grace & Edmund)
Constance Mabel Martha (Edmund & Beatrice Agnes Constance)
Florence Ellen Fiona (Freddie)
India Grace Kelson (Rufus Andrew & Sofia Grace Kelson)
Minami
Ophelia Emily Phyllida
Penelope Mary (Millie Elizabeth)
Poppy Anne Lillian
Sienna Rose (Arabella Fflur)
Zazie Clara Elodie (Otto)
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.