Most people will interact across more than one MSOA, but from map watching I would say there tend to be tight connections where there is a lot of interaction between certain linked MSOAs or within certain MSOA; those are the ones where the virus really digs in, with lots of infections following. Local links include transport, hospitals, care homes, shopping centres, workplaces, universities or schools. People travelling across MSOA then spread it further, but the majority of the time during lockdown people haven't been going too far. Regardless, a few cases can come and go without it being an issue, it's the MSOA with lots of cases that are a concern because the probability of undetected cases in those areas goes up.
There are some MSOAs with a lot more deprived areas (particularly with flats) where the Kent variant was better able to spread; and large numbers of cases then always infect neighbouring MSOA, sometimes in specific directions. Kent variant in West London had clear spread starting in Wimbledon that hit several pockets at once (students / pub?)... they each took a little time to diminish and it might have slowed... apart from Malden Manor (tower blocks) where closer proximity and lots of interaction in the local area led to cases rising and rising, massively affecting schools for the first time in the area and spreading further into every neighbouring MSOA, then spreading east right through Croydon and up to Tooting as well as west into Kingston. In Kingston it hit Chessington hard and then spread into Surrey (theme park not open!). Croydon spread steadily south to hit to Sussex coast and the West side of Kent itself that had totally avoided the cases in east Kent, which had instead spread to Essex. Tooting and Croydon together had a gradual spread east to catch up with the variant spreading westwards from Kent itself. You can adjust the dates on the map to watch it from mid November, just stay centred on Malden Manor.
Sorry, I'm not sure if that's helpful to the discussion or just me chattering on.