After doing some digging on the Dartmouth Arms after my last post, I stumbled across the plans for the ex KFH unit on the Lewisham planning portal (only lodged last week) - https://planning.lewisham.gov.uk/online-applications/applicationDetails.do?activeTab=documents&keyVal=_LEWIS_DCAPR_133242
Appears to be a full renovation of the existing estate agency unit to a new Pilates studio trading at Mind & Motion (mind-motion.com). They have one on Northcote Road and Streatham High Road.
I think it’s a good use for the site and type of operator.