Step 1.
Do basic police work, arrest perpetrators.
Step 2.
Charge them with crimes.
Step 3.
Convict them and send them to prison, ideally covering the summer months. Remove illegal vehicles from road.
Step 4.
Deport back to Ireland where possible and bar them from future entry.
Step 5.
Apologise profusely to residents for years of inaction.
Problem is they'll fail at No 1 by not being able to identify who did what, and as a result won't have anyone to charge with any offence........and even if they did, convicting them will take months, and probably wouldn't result in prison anyway. Hugely frustrating, as all the time they trip around ***ing up public spaces, intimidating locals and leaving their sh*t everywhere. Probably need some new legislation to deal with it - but of course there will be 'human rights issues' if we try that.