Does anyone know the name of the purple flower (or weed) shown below? We are in central Scotland.
It is an Aquilegia, common name columbine - not sure if it's a named variety you planted yourself at some point, or whether it has seeded itself. If it has seeded itself, you're very lucky it's this colour - they usually turn out a sort of dirty pink when they're self set. It will drop seed after the flowers are finished, so if you don't want it to do that, cut down the flowered stems to the base when they're done. If you do want it to seed, cut the stems down after the seed has gone.
There are a lot of hybrids of this plant in quite a wide range of colours, including bi colours and double flowered forms. Some examples here https://www.rhs.org.uk/Plants/Search-Results?query=aquilegia