That's really interesting, Cos. We are knee deep in buttercups at our donkey sanctuary and are having precious little bother with flies this year. The tails are very busy, mind you, but none of the animals are being all that bothered with bites, etc. Like other people who have posted, this is the worst year we have ever had for buttercups - makes you hang your head in shame at bad land management - but I really had no idea they would be as thick as this.
Will be getting the soil tested for ph levels and thinking about spreading lime for another year.