your other yellow flower is Blackstonia perfoliata - Yellow-wort. This member of the Gentian family is a locally frequent plant of open calcareous habitats, north to Northumberland. It has several distinctive features 8 - but sometimes only 6) petals but easiest to spot are the rather greyish leaves which are connate, i.e. fused together so they wrap all the way round the stem (perfoliate).
Your other plant is the Common Bird's foot trefoil - telling it apart from the Horseshoe vetch generally is easy if you can see the leaves - they are pinnate in the latter , i.e. with lots of smaller paired leaflets - it also has more flowers which radiate all the way round the top of the flower stalk, not fewer, randomly arranged and often at slightly different heights on the stalk. The fruits are very different in shape too. Telling Bird's foot trefoils apart is a bit trickier but looking to see whether the stem is hollow, the arrangement of the sepals and the shape of the leaflets and whether they are annual or perennial does it.