Normally the species I suggested has a long 'tail' on the last segment, but I can't see it as it's covered in goo. Can you remember if it had a tail? The species I suggested don't aggregate in large groups and mainly feed on forbs and climbers, so that seems about right from your picture.
Hi Sam, I have added a further photo without the "goo" but unfortunately still rather obstructed. It then disappeared deep into the vegetation so I could not get any more photos.