Customer (being polite) invited the Police into the argument using false allegations that you can prove false as you have the recording.
I suggest that you head on down to the Police Station, first to get a written record of the officers who attended (potential witnesses) second try having a word with the officer in charge looking for Fatherly advice etc some love to be looked up to.
Ask along the lines about having the customer charged with fraud and making false allegations, wasting police time, trying to ruin your reputation etc
In Ireland the Police are not obliged to get involved in a "Civil Matter" however when they see one party to a dispute being totally unreasonable they do have their ways of making life uncomfortable for the scum bag, little details like speeding fines for 32 mph, parking fines when front or back bumper are over yellow lines, regular visits to the house sometimes leaving the blues flashing while asking him how the heating is working, maybe following a complaint that you now have a scratch on the van you didn't see before all this blew up.
Make a few copies of the recording store them in different places for later use, does your wife / partner cry easily? if yes bring her along to the Police Station feeling all worried and threatened after hearing all the bad language on the recording etc
You need all of the law on your side and since he opened the door to the Police use them to your advantage, as franky said never swear or raise your voice even if talking with the nice Policeman about Mr. XYZ never called by his first name even today appear to be respectful toward the *#@^
Don't wait to bring your Solicitor into the picture, the moment he called the Police all chances of you ever making the alterations to his liking flew out the door, also why we all would like to help your Solicitor may give the best advice.
Try to have decided on whatever action you must take in the next few days but it in play and move on with your day to day business, incidents like this happen but are rare don't let the bar stard poison your view of every potential customer because that way he is still costing you money.