In reply to jon59:
In February 2017, I used the following Kenyan company to arrange the logistics of my climb up Nelian, including a Chogoria – Sirimon Traverse.
http://www.gotomountkenya.com/
The arrangements, logistics and entire trip was superb. I'd certainly highly recommend this company, in particular Evans Mwangi who made all the arrangements and was very helpful and professional. I made a short video of the trip-might be of interest too? -