Well...... the udder cream has worked wonders overnight, and they're also on better grass now and not as eager to run when they see me with a bucket (that may be the heat though). I'll keep an eye and whip a couple of the lambs off if she gets any worse. I'm also going to put some creep feed out, since that may lessen the pressure a little too.
Ideally we wouldn't have left triplets on either, but unfortunately all the ones with singles lambed first, so it wasn't to be. I think that's one of the problems with having firstly a small flock, and secondly Zwartbles!