Template options missing WP 3.1

Hello,

On adding some page templates to a child theme I’ve discovered the template options drop down menu which usually resides below the ‘parent’ drop down on the page editor is missing – not sure if it happened on latest update to 3.1, but other similar setups not yet upgraded are fine.

The templates themselves are in place and correctly formatted with name etc.

I have read other threads such as this one: http://wordpress.org/support/topic/page-template-problems-with-26?replies=20 however, I am reluctant to swap themes to reset as the site has a complex widget set up and my understanding is that they get reset or at the very least disrupted with a theme change – and a test on a dev site seems to confirm this.

The above thread has some other fixes but they are out of date. I realise its possible that something more specific maybe causing this, but I’d like to try the ‘reset’ type option first.

Is there another way of letting WP know there are templates available?

thanks