UPDATE…
Answering my own question, I’ll add this in the hope it’ll be useful to someone…
Whilst waiting for answers, I found a solution which seems to work fine.
function remove_images( $the_excerpt_rss ) {
$postOutput = preg_replace('/<img[^>]+./','', $the_excerpt_rss);
return $postOutput;}
add_filter( 'the_excerpt_rss', 'remove_images', 100 );