Emmanuel,
I have a copy of the medal with the purple ribbon in a group of 5. It is in fact the commemorative medal for the 25th anniversary of independence. On the reverse is the Kenyan coat of arms and the teaxt "MIAKA ISHIRINI NA TANO YA UHURU" then "AMANI" on the left of the coat of arms and "UFANSI" on the right with the date "12 DEC 63 - 12 DEC 88" underneath.
Of course I am making the assumption that the medal is mounted on the right ribbon!
I'll try to find the right technology to enable me to post a photo - not always readily available where I am.
Tim