title: Regex to remove all but the last occurrence of a single character
body: <p>Our sanitisation on a salary input replaces all characters other than numerics (0-9) and points (.) with a blank string. </p>
  
  <p><code>[^0-9.]</code></p>
  
  <p>Which results in a string like "£63,000.00" becoming "63000.00", which can easily be converted to a float. Now I want to sanitise the case where users have used a point as the thousand separator as well as the decimal separator (eg "63.000.00"). How would I write the regex to remove all but the <em>LAST</em> point character in a string? </p>