advise please

First, deeply sorry for your loss. 

I rarely call the UK nor Europe so my answer may not be so accurate...

The cheapest mean would be Skype or VoIP through Internet, but then again you need to have a good Internet connection and it is not the case in Kenya.

Another way would be to get a mobile phone from either Safaricom, Zain or Telkom-Orange and enquire at each office about their prices for international calls.  Like in my case, I am on Zain and when I add a special number before an internetional number, the call is made in VoIP through the provider and therefore I pay little compared to market price.

Otherwise, an ultime solution, is to get Telkom calling card specially made for International call.

Hope this helped.

Regards,

Peperuka

i agree with peperuka, but if you really want to save there is a place in Highridge called Diamond Plaza - any cab guy in westlands will know it - just go there - they have some booths / shops that offer really really cheap calls overseas...
but my advice would be to use Telkom kenya / skype