I used Hassan Gindeh who operates from the hut opposite the Senegambia. He was excellent, knows everyone and is respected by them, a good conversationalist and doesn't put you through any awkward unscheduled side trips. I'm grateful for him putting together a Brufut/Tanji trip which enabled me to see some superb birds (Bronze winged Courser, 3 Owls etc) whilst still keeping my non-birding wife entertained with the local sites.
He was extremely affordable too.
There are some pretty average guides in Gambia so it's well worth taking recommendations. Hassans number is 7040618, just get your hotel to call him. Website -