Common Toadflax (Linaria vulgaris)
This is natural version of the flower we used to grow in the garden, Common Toadflax.
As the name implies, it is fairly common and thrives on calcareous soils and hence does well in parts of Dorset.
It flowers from July right through until October and you can find in waste areas, on grassland, in hedgerows, along roadside verges and railway tracks, anywhere where the competition from other plants is not too great.
I have also heard this called Tom Thumb and Eggs and Bacon but I think both of these country names really apply to Bird's-foot Trefoil.
Common Toadflax is a lovely flower, well worth taking a closer look at it if you find it.