I realize you want to find a lever harp version, but sometimes lever harpists who cannot locate exactly what they want, find a pedal harp version and modify it, leaving parts out, omitting doublrd accidentals, and so on. There is a beautiful pedal harp version of the second movement of that concerto, published in 1989
Holywell music in London should be able to get hold of it for you, and i think that they’re your best bet. If not, try Morley Harps at http://www.morleyharps.co.uk