Heyy Keryyyy just seen this.
As I said once they got back to yours I would be expecting a few scuffles.
It sounds like to me Milly has became so relaxed around Patches (which is a good thing! as at first she was very nervy about him) that she is now quite happy to be a bit bossier :L This has probably confused Patches a wee bit and as I said I observed when they were with me he can get a bit nippy (I think its whenever he is a bit anxious). Anyway there has never been any signs or real aggression from either on them, so I wouldnt be too worried and I would leave them to sort it out in this new space, they should soon settle. Though I would obviously watch Milly and make sure her pestering dosent increase to the point where Patches is severly distressed. But if all he does is turns around and give her a quick nip I would leave it. And as said please feel free to contact me if you need any help