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 James
Alexander William
Alfie Edward
Arthur Herbert Theodore (Florence Amelia Mari; half-sibs: Freddie, George & Lily)
Benjamin
Dougie Leigh
Eddy Eames (Arthur)
Edward David
Henry Gareth
Henry "Harry" William Clarence (Mirabelle Lula Rose & Cecily Charlotte Alice; half-sib: Parker)
Jasper Michael Louis (Kit Nicholas William)
Leander
Leonard Lewis
Nairn Thomas
Noah Sameer
Rory James Morris
Theodore "Ted" (Angus Lyndall Patrick)
Girls:
Adeline
Alexandra Georgia Sofie
Amelie Elizabeth Rowena
Atia
Cassandra Juliet (Zachary)
Etta Grace
Florence Theodora
Grace Jennifer
Margot Isabelle (Wilfred Humphrey)
Rose Alison Allegra
Rose Elizabeth Jane Zia
Rosemary-Artemis Isabella (Alan Horatio)
Stella Grace Auldio
Willa Lucy
Twins:
Holden Patrick & Knox William
Matteo George & Luca Fredrik (Isabella & Georgiana)
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.