Neighbor with cars without insurance/tax/mot

We live in a residential area where parking is limited and one side of the road is like a pavement where a residential permit is not required.

We have a neigbour who is/was a mechanic and has a history of parking his cars (now 5) which does not have tax, insurance or MOT, some have at least one but none of them have all three.
There is one car does not have tax, mot nor insurance.

Please advise what can be done as sometimes it's impossible to find parking returning home from work.