Answer, nobody knows for sure, simply because Lotus didn't keep accurate records.
Here are some best guesses.
5,228 - Jabby Crombac - Colin Chapman the man and his cars. 1986
5,200 - Lotus Press release 1986.
4,600 - 1,600 +2 and 3,000 +2S - Chris Harvey - The Elite Elan and Europa
4,526 - Robinshaw and Ross - Authentic Elan and plus 2