Thanks for your help @Sularomo.
I’ve managed to get the code working and in the process found three ways to get around the parsing error.
Hope this helps those others are also looking at ways to show selected posts in a specific order. This can be used when the “ordering” and “orderby” criteria in the other “#get” helpers can’t achieve.
The next thing I hope to figure out how to select the posts I need in sequence from a list rather than hardcoding the string of post IDs.
<!-- Method 1 - Replacing the double quotes with single quotes -->
{{#getPosts "3,1,2" "<section class='posts'>" "</section>"}}
<!-- Method 2 - Escaping the double quotes with \" -->
{{#getPosts "3,1,2" "<section class=\"posts\">" "</section>"}}
<!-- Method 3 - Taking out the HTML prefix and HTML suffix and place them outside the #getPosts helper -->
<section class=\"posts\">
{{#getPosts "3,1,2" "" ""}}
...
{{/getPosts}}
</section>