New kid on the block

I've been watching this kid. A couple of weeks now. How do I know it's a new kid?
He, or she, is sandy brown,much paler than any of the foxes we had this summer. The tail tag is different from any of them too - not ragged, or rounded, or absent.
The throat is very dark, like the Halftail/Ragtip group and rather unlike most of the foxes we have watched for a decade.
This kid behaves differently, too.
Only yesterday I was watching from the bedroom with binoculars and he noticed me. Out of mischief, I opened the window and instead of ignoring this as familiar foxes would have done, he gazed up in alarm and scampered away behind the shed! Our previous tenants would never have done that. This guy is much shyer, or not used to the local regime as yet.
Sandy, as I shall now call him, is clearly the one who has been feeding in my garden. He is often accompanied by another, redder fox who sleeps in the garden at the same time though not with him. I'm guessing that this is still Roisin, looks just like her. I'm also tempted to wonder if Sandy, and not Ragtip, was the target of the "seductive urination" or whatever it was, see second-last post.
What has happened to Halftail? To Ragtip? We may never know. This happens every year and I have become as matter-of-fact about it as the foxes are. Autumn is the time of dispersal, of empire-building. It is also the time of roadkill, lots of corpses on the nearby N11.
We will see what the next season brings.