In Cockney rhyming slang, “Face” is Boat Race.

In the list, it is Oxfordshire and Cambridgeshire (the boat race participants) that have been transposed (hence “About Face”). The counties have been listed according to their initial letters and how they relate to the atomic numbers of the elements in the Periodic Table.

H – 1- Hydrogen, Hampshire

He – 2 – Helium, Herefordshire

Li – 3 – Lithium, Lincolnshire

BE – 4 – Beryllium, Bedfordshire

B – 5 – Boron, Buckinghamshire

C – 6 – Carbon, Cambridgeshire

N – 7 – Nitrogen, Nottinghamshire

O – 8 – Oxygen, Oxfordshire