The original ticket on this Constantius said 'ex Caen hoard'. Searching online including University Oxford database I can't seem to find anything with the right dates nearer than Treasure of Saint-Germain-de-Varreville - maybe 100km from Caen.
There's a Caen hoard mentioned by Ashmolean but last dates is Tetricus 270s whereas this Constantius coin is 296 struck at London mint.
Constantius, as Caesar 293-305,
Æ Nummus, 26.5 27mm, 10.09g, 7h, Londinium, 295 - 296;
Obv: FL VAL CONSTANTIVS NOB C, laureate bust right, B1;
Rev: GENIO POPVLI ROMANI, Genius standing left, modius on head, naked but for chlamys over left shoulder, right hand holding a patera, left cornucopiae, LON in exergue;
CT 1.01.008, S Scarce, RIC 4a;