<?php
$string = 'A lead was space" ema il "@emailadds.com saved for sharon.davis@website.com, Date: 11th December 2019, Service: Car Hire ( Premium ), Extras: NA, Price: £300';
echo preg_replace('/(?:[^"\s@]+|"[^"]*")+(?=@[^\s.]+\.)/', '******', $string);