I thought the advice/legal requirements at the moment are that travel anywhere, except for work or other exceptions is not allowed: this is taken from the government website:
you must not travel in the UK or overseas, unless for a specific reason, like education, work or a caring responsibility
Therefore, your colleagues are not complying with the lockdown requirements.
Govt announces Ukrainian style scheme to bring thousands more migrants to UK


), but to me this is an important, temporary situation where we have to think of others as well as ourselves. 