[I am Richard Brandon]

Get a Grip!

7s 6d is a very normal charge in Old Sterling:

7 shillings (no letter c) and 6 pence (d = Latin denarius)
7s 6d = seven and a half shillings
7s 6d = three eighths of a pound sterling

I know that we were dealing with East African Shillings, but the mindset came from the British who used Pounds, Shillings, and Pence.

Wikipedia says the EAS and pence were replaced in 1966 by the Kenyan shilling and cent.

[Tellurian]

Before 1966, Kenya had East African cents, not pence, as shown with these coins from the '40's & '50s. It appears it was a decimal system: this 50 cent 1949 East African coin (on e-bay) doesn't fit the 12 pence to the shilling rule as it does in 1964 Australia.