Vicia balansae
As is so often the case with plants from this region, the names in the Russian flora of the Caucasus region don't agree with Plantlist1.1. In this case the plant is listed in the flora as Vicia truncatula ssp balansae which before that was Vicia abbreviata ssp balansae. Plantlist says that Vicia truncatula is a synonym of Vicia abbreviata but Vicia abbreviata ssp balansae should be Vicia balansae.
From this and some of the images posted on various wild flower blogs I assume this is Vicia balansae which is found mostly in the region between the Black Sea and the Caspian Sea much of which is the Caucasus mountains where our Greentours trip was based.
Lagonaki National Park, Russian Caucasus 21st June 2016
Added on August 5th 2018