Hi Alison ... sorry for late reply - I've only just spotted your post!
I haven't come up with anything new since I last posted but we've tweaked our ILP paperwork and are now going to try reviewing learner progress four times a year - including a summer term. Hopefully this will quickly flag up any issues which learners are having, and if a pattern of no progress against stated learning aims can be established, then we can step in and see what can be done for the best. I don't think the issue of moving learners on has any easy answers!
Hope all is well in the North! :-)