MapServer PostgreSQL WHERE clause with UUID column fails

Question

I'm using MapServer with PostgreSQL and I need to be able to limit the query using a UUID field. This column type is not mentioned in the documentation.

I can happily use other field types in the WHERE clause e.g.

DATA "geometry from (SELECT id_uuid, geometry, projectid, style_description from project.mytable where ukcode = 'a4c' and area_hectares < 0.0001) as subquery USING unique id_uuid USING srid=27700"

that works. But when I try and use a uuid column in the where clause like this...

DATA "geometry from (SELECT id_uuid, geometry, projectid from project.mytable where projectid = '61ff8678-8e45-496b-9aa8-f72b9a328175') as subquery USING unique id_uuid USING srid=27700"

I receive this error

msWFSGetFeature(): WFS server error. ms_error->code not found msPostGISLayerWhichShapes(): Query error. Error executing query. Check server logs

I can't get the error logs working which doesn't help.

I've also tried casting e.g. '61ff8678-8e45-496b-9aa8-f72b9a328175'::uuid but same result. I've also tried this in a Filter but its the same problem.

Have I got the correct syntax? Does anyone know - should I be able to query by uuid? Perhaps this isn't allowed but its not in the documentation