As per my understanding i think its different when you send email inquiry to chc london and chc-isb (although seniors would disagree with me here but i would like to share with you guys esp for those who are waiting since 2008/2009 like me).
In case of chc-lsb they used to send standard replies in my case (pre-prepared statments), but in case of chc-london they tend to get back with specific replies(e.g. if got waiver of fresh ppc from UK through email at the time of medicals) if not the positive outcome straight away. please note my observations are for applicants under M1 and M2 only.
In my case ecas address never disappeared for PPR1, however exactly two weeks back i sent them a politely written email asking if they need any thing else to process my case (u know just kind of soft reminder). They never replied to me after that but after exactly two weeks from that email they sent me PPR-1.
What i am implying is that if you wait for 3 or more months after medical and nothing comes up may be you can inquire in a polite way and it may help diverting their attention towards your case . Its just my observation though i am no qorax, leon etc. I am just a learner!
Best Regards.