thanks again for the reply, so we managed to get it working, it was the scale range in the feature service that was at fault, the max had changed (not sure how) to 2500. I only noticed after I went back and checked, it looked like the server had cached the settings so once I changed them I then refreshed the service and it worked for some of the users.
But it didn't work for all of the users it looked like the old settings had been cached also on the users devices, to resolve this the user had to delete and re-install collector or the other solution that worked was to save a copy of the map but with a different name.
thanks again for the help