you can apply to the land registry for a copy of their office copy entries to the property and see if they have whats calleda restrictive covenant in there preventing them from running a business, either way, you could approach your local council and ask them to take steps as the business is a nuisance to you. As to the garage, again you'd have to speak to the council and find out whether they ever made an application for the building.
blocking of driveways is a pain, we have that too, i'm afraid thatthe council will not be bothered about that and unless you can talk to the neighbours about it and ask them to stop, your only other option is to call the police and tell them that the neighbours vehicles are obstructing you from moving your car. Try to avoid a neighbour dispute if possible and let the council be the bad guy (if they will help {LOL} as disputes can be a real turn off for prospective buyers and can make your life very difficult