If you are staying in the Greenwich accommodation there is a shuttle bus that goes to and from the two sites, it would also be quite easy to get the train (as long as there aren’t any strikes or delays) and shouldn’t take very long to get to and from london/the uni. For placements I was discussing with someone in April and they take into account students travels and reimburse any travel expenses for placements and will only expect you to travel a reasonable distance from either the uni or where you are staying, they did say however if it’s a bit more of a specific industry for a placement that isn’t available locally they would expect you to be willing to travel there if it’s what you want to do but again would reimburse for reasonable travel expenses, this is what I was told in April but it may be good for you to ask too just to confirm