Thank you! I am hoping we don't have to redo the medical. London VO has been frustratingly slow after getting off to a very quick start.Good that London VO moving fwd your application. keep eyes on your ECAS there is chance that your file status update soon to DM, as per tracker from London VO few applicant got DM within 2-4 week after pre arrival service letter but in your case your medical soon expired.
Keep eyes on your Ecas for DM & myCIC to check your medical passed date . if they make decision before medical expired VO give you extension for medical and will update Ecas to DM.
Thank you for your input Robert!