Lyonetia clarkella perhaps on Rhamnus cathartica - or not?

 

I found a tenanted corridor mine on what I initially thought was a Common Buckthorn tree in Dene Park today. The mine was very thin with a central line of black frass, and solely on that basis I wonder whether it might have been Lyonetia clarkella. However the larval shape and its green colour did not look quite right.

This is the underside of the leaf:

and this is the upperside.

However maybe as a consequence of this result just not fitting anything sensible, I would have to conclude that the leaf is just not Rhamnus cathartica. So, have a look instead at the next two photographs, upperside and underside. Here you can see that the leaf has many more obviously rounded teeth on the margin, so is much more likely to genuinely be Rhamnus cathartica. There is a long gap marking the last position of the larva, and the mine has crossed the veins and the midrib freely. My best guess is that this actually is Lyonetia clarkella, although it is not supposed to be found on this foodplant in the UK as yet. What other alternatives are there, as it doesn't look at all like the hairpin mine of the only UK-named species on this host, Stigmella catharticella:

Because the mine has been vacated, this ID cannot be officially confirmed, but..... I think this is fairly good evidence for the first record of this very common leafminer on this particular host in the UK! Nothing like being ambitious!