To my knowledge no office anywhere in the world is doing in-person. They have apparently said virtual interviews only, few actual reports of pre-arranged interviews (but some) - not specific to London though.
Some applicants have noted being called on phone and asked some questions apparently in lieu of interview.
I do not know for certain but it seems this is a global decision; presumably they will relax in some places sooner (eg your point about UK) but it is up to IRCC to decide so we can only go by what offices actually do (unless and until IRCC announces something publicly).