Yes it is London visa officeI see, you can also contact your nearest Canadian embassy and they will help you certainly. since you have PPR email you will be soon getting email on next step. wait for 1-2 days if possible.
IRCC usually takes 5-7 business days to reply to emails but mostly generic replies.
May I please ask if your application was moved to LDN IMMIGRATION AFTER MEDICAL?
They take a very long time
I had pre arrival lees about a month ago and no updates after that except the DM two days ago