To make all 10 modules fit in a tighter space I rotated the antenna cable so the antenna was on top of the board and going over the metal enclosure of the u-blox module. It turns out this is a bad idea.

The modules like this won't get a fix and sometimes nearby modules with the antenna in the previous position will also lose their GPS fix.

Flipping the antenna to the back of the board seems to be OK, and it looks like the solder pads might have been designed so a 25mm antenna could be soldered on.