Sorry about the poor photos,
I think I've mistakenly double-added these to the wrong picture library, sorry.
It landed on my arm so unfortunately you get to view my hairs as well.
Looks like a very large blackfly to me,
About 6mm long including wings, so much larger than an aphid-type fly.
The middle picture shows it's got heavy duty piercing / sucking mouth-parts (?)
Not noticed this type around the pond before,
it was very clumsy but managed to take of eventually.
Any chance it can be ID'd from fuzzy photos ?