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:
Caspian Aubrey Peregrin (Leander Francis Bertram)
Harry Robert
Ralph Hector
Rupert William Oswald (Frederick Arthur Maurice)
Sebastian Edward Moses (David Alan Olaf & Verity)
Theodore Ernest William
Girls:
Annabelle Charlotte
Astrid Felicity (Alfred Willis)
Cecily Mary Helen (Augustine Joseph Mostyn)
Charlotte Avril Alethea
Sophie Elizabeth Grace (Alice Catherine Sophia)
Twins:
Gray Clancey & Elwood Clancey
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.