Marigold - yeah, its always the hens nearer the bottom of the pecking order who struggle to accept newbies. They had three weeks or so staring at each other across a couple of feet of path, and thats worked just fine previously. Really surprised it hasn't worked this time, but you live and learn
The younger girls are perfectly happy with Bess and Matilda. Bess the old speckledy especially has been cosying up with them on perches, and while she'll peck them once so they know who's boss, she's just as good a boss hen as she's been integrating chickens previously.
Dinosaw - the run I've got is a funny shape, and the house is really big - the shading in the footage kind of shrinks the interior of the inner run rather, its comes further back past the recording position and further forward than the end of the outer run. There are places to hide out and chill out for some personal time when a hen needs it, but this time round Edie (the cream legbar) has been pursuing the youngsters quite remorselessly. Not had this before - but I'm sure it'll sort out.
Anyway, I sat out in the inner run and allowed Mary in there for half an hour this evening, with no particular trouble (put the younger girls in their place and then all was well). Will continue with this, Mary again tomorrow, and Edie later in the week. If it takes a few weeks, well, there are worse things that could happen.