Our update just says "We started processing...xxxxx" but nothing about medical. I'm a little worried about this since we completed medicals in late June, a full 3 months before submitting our application in late Sept.
It's a tough one to know exactly what is happening. As you know from my answer on another thread, I had both "We Started processing..." and "Medicals Received" on e-cas. These messages appeared at the same time when the PR status changed to "In Process" rather than say "We Started processing..." first and then a week later "Medicals Received". BTW if it helps any, E-cas in respect of the London office, is updated weekly on a Monday, so I used to check every Monday evening or Tuesday first thing. I don't know what the routing was for your medicals but I had my medical done in Canada (Halifax, NS) as I was visiting and the medical and subsequent application were done within a month of one another. Although time frames may not affect the chances of stuff going missing as I believe from reading other answers on the forum that the 'local office' processing your application requests the medicals from whatever regional medical office your medicals were routed through. Also, if you did your medical in the UK, the RMO is at the same address as the office that would handle actual application. So, maybe in this case, they just don't acknowledge the fact that medicals have been received because they were already at that address, but in a different department.
I found that because it is quite difficult to determine how all the different bits of the process fit together, that makes it difficult to know how or when to chase up any anomalies between E-cas and the perceived reality of 'the system'.
However, be very careful contacting London about case specific stuff where it might result in them having to pull your actual file out as it can slow down the application. The problem is weighing up the effect that a question about your case may have against the possibility that the medicals have not yet married up with the application (if that is what they have done) and the effect that may have. Maybe a general question about E-cas updates may suffice.
Hopefully someone else on the forum may have a more detailed knowledge of what goes on 'inside the box', as most of the time, as an applicant, we all seem to have to determine what might be going on by sort of reverse engineering the process from the available forms and E-cas updates. Unfortunately the only 'appropriate' time to contact a visa office seems to be after the final PR decision has been made or if a certain amount of time has elapsed after an update to E-cas is made and you've not heard/seen anything else - six months I think, in the case of the London office
Unfortunately, my answer may raise more questions that answers. But, having reached the end of the process myself, apart from the landing bit, I know exactly how this uncertainty feels.