You Do Need power plug adapter while traveling from Falkland Islands to Sierra Leone.

Here is Why You Need An Adapter

The outlet and plug type used in Sierra Leone are D and G and in Falkland Islands is G. This is how they look like.

Falkland Islands

In Falkland Islands, outlets of type G are in use.

Type G

Sierra Leone

In Sierra Leone, outlets of type D and G are in use.

Type D

Type G