May I ask if these are the male and female of the same species or two separate species?
No interactions present.
After taking a closer look at the photo (on my PC screen, rather than on my phone), I can see that the female is a Common Darter not a female Black Darter.
This might explain the behaviour, which looks more like predation than an attempt at mating, although males are sometimes very clumsy in there attempt to grab a female - especially if the female resists the advances (which is likely when, like here, the female is a recently emerged individual of another species!).
The white pterostigmas (the spots near the wing tips) show that this is a fairly recently emerged female, which helps explain why she was less able to avoid the smaller male.
Identification features that can be seen if you look closely are: the lack of an obvious black underside to the abdomen; the pattern on the side of the thorax (Black Darter has a broad black band with three relatively small yellow spots within it); the lack of black extending down the side of the frons (face); and (perhaps the most obvious) the legs - which have clear yellow stripes on them (all black in Black Darter).
Lat/Lng: 52.57443, -2.94947
OS grid ref: SO357978
At the reservoir at The Bog