Bullfinch, Pyrrhula pyrrhula feeding on Buddlieia

I came across a small flock of these (around 20) whilst out blipping this afternoon. They were on waste land where a lot of Buddlieia bushes thrive and they were feeding on the seeds.

Now, I don't know if you are aware, but Buddlieia seeds are minute - not much bigger than dust! I don't know how the bullfinches coped or whether they swallowed the whole seed capsule. Whatever method they used, it was obviously a good source of food because so many of them were feeding there for ages.

Surprisingly, when I Googled 'bullfinch Buddlieia', I got no results for them feeding from this bush. Could it be a new development of their behaviour?