I haven't listened to a lot of Peter Davison's stories, but I definitely reccomend SINGULARITY. Featuring Turlough as the companion, its set in near future Moscow and features some quite interesting alien opponents. And its a good old fashioned time travel story. None of this bloody 'alternate universe' stuff that honestly gives me a damn headache.
Theres some possible conflict with the tv episode Utopia, but some quick speculation on the listeners part should fix that.
Two thumbs way up.