Yes, that's an excellent choice if you have the space. Leaves can get 4' across and 8' high. They love low-lying boggy ground, full sun & lots of rich compost.

Impossible to say where it would look better without a photo.Sounds as though either site would be ideal but if the drainage ditch sometimes gets dry for a longish while the pond might be better.

Thank you ditch usually has 3 to 4 inches in it maybe if I could clear a site on opposite side of pond (boundary with unused allotments)this would improve the visual effect, thank you very much