I've read stories about right wing extremists using the English flag as a mean to show their support towards anti-immigration sentiments and to make immigrant people feel unwecomed in their neighborhoods but I am not really in the loop and I would wait for someone more knowledgeable than me to provide you with an explanation, especially because you identified the area pretty well. Could be that there's a festivity going around I am not aware of and that there could be a not-so-dark explanation for all the flags