Please remind me again, why is there a StuG on this map? Of the units in 21st's TOE at the time, Sturmgeschütz-Abteilung 200 did not have StuG's, but Marder I's f all three variants: Lorraine, H38/39, FCM; plus a few 10,5 cm leFH 18 on those chassises as well. Panzerjäger-Abteilung 200 did not have StuG's either but towed 88's.
Also, the date on the website. While Operation Charnwood did indeed begin on 8th July, 3rd ID ran into 21st in Lebisey on D-Day already (as it says on the map description!). During Operation Charnwood, 21st had already been relieved by 16th Luftwaffe Field Division, which only got a battallion of Panzers from 21st as support. If the battle is supposed to represent the latter - which I doubt - the StuG is again out of place.