I too very much fear what will happen when the EU workers in care homes, as HCAs, as hospital cleaners, leave.
I work in the NHS. I think the issue we had with the Romanians was they pretty much come from one small area in Romania, so the jobs (floor polishing, kitchen hands etc) were filled via word of mouth, someone's cousin, etc, so they arrived already knowing people and soon a clique is formed, one composed of quite a few poor-English speaking young men, who band together and thus feel protected in their 'gang'; so, like another poster, people would see them huddling together in a group (at work), hear their own name spoken, followed by a roar of laughter.
They also took great exception at being asked to do a task by a woman! There was always an undercurrent of resentment.
We'd never experienced this with any other EU group, and god knows, we've relied on enough over the years!