Dizzy, you are lovely 
The thing about AMH is that, depending on who you speak to, the test is either a nonsense or it is a revelation. I hear women in their forties who get a result of 0.01 (appalling) and say 'Oh the test proves nothing. It only makes assumptions about ovarian reserve; it can't tell you what quality our eggs are'. Then you will get another woman in her forties (me) with an AMH of 5.5 who will keep TTC feverishly thinking my score is brilliant for my age and it's the best test since sliced bread (5.5 is not brilliant by-the-way, but it's fairly good for a 43 year-old).
My view (and that of my consultant), is that it is a very good indicator of both egg quality and ovarian reserve. I like the test, but I wouldn't if my score was shit. Sorry, I'm rambling. What I do know is that Gennet clinic in Czech Republic (the European leader of IVF treatment) will not touch you with a barge pole if your AMH is below a certain level. Clearly, it seems to me, they won't risk their success rate statistics being sullied by women insisting on using their own crap eggs instead of the clinic's donors' 