Some statistics about immigration detention (and remember that most of these people have committed no crime other than being here without the correct visas)
The majority of those in detention will be held for less than two months, but in 2019 26% were held for more than 28 days. This includes 167 people who were held for more than six months and 13 people for more than 18 months. The longer someone is detained, the less likely it is that they will be removed from the UK.
The UK is the only country in Europe that doesn’t have a time limit on detention.
In 2019, 24,512 people left detention. 30% were removed from the UK, which means that 70% of those detained were released back into the community, their detention having served no purpose.
In 2019, the longest recorded length of detention was 1,002 days. That's over three years.
So 70% of people detained turn out to be entitled to stay here. Now do you see why neighbours on this occasion tried to prevent these people's detention?
The HO know who they are and will doubtless continue to investigate them. But the odds of them being entitled to remove them from the country are less than 1:3. A dawn raid is hardly appropriate.