The DMP does not send the medical results to the CIC processing office - they send the results to a Regional Medical Centre and that's where they're held until the processing office requests them. DMPs in Canada are accustomed to sending the results to the RMC in Ottawa and sometimes they can be really uncooperative about sending results elsewhere. But only Vegreville (as well as Buffalo and some other processing offices) request applicant's results from Ottawa.
London will request the results from their RMC - so if your DMP has sent the results to the RMC in Ottawa, you'll want to try to contact that RMC and see if they can transfer the results to the RMC in London.
Here's a list of all the RMCs with address and fax numbers.