All great food for thought. In the end I doubt I'm up to sorting this out by myself, just not enough experience. So I took the problem to a sewing class I've just rejoined this week. The tutor has me remake the muslin from the original pattern (without adjustments) and we will take it from there. She will see what's what and advise me what pattern changes I need to get the fit right. Could be a third muslin looming but that's ok - I want to learn and I'll post feedback here in due course. Thanks all.