Going from MEP to IP2 is common for CEC-applicants - but I've seen it happen for FSW-applicants too...probably because you applied for visas before and there's good exchange of security information between Canada and the UK, they can progress quick with your application.
You are never required to provide a PCC for Canada - they will sometimes request it as ADR though if there's some doubt about something (e.g. name matches with that of a criminal) but this doesn't happen too often.
With AOR July 3 my guess is you may get PPR sometime in OctoberMy AOR is Juny 29 and I had my application approved August 30 (but still awaiting PPR mail).
Just stumbled across this post while searching the forum to see if my previous IEC visas might be causing my delay, perhaps Canada are taking their sweet time to ask me for fingerprints or RCMP PCC. GCMS notes ordered today, so we'll see. Anyways...the October estimate and speedy hopes have been long lost.