Thanks a lot for your support @craig we were able to build a plugin for the Z1. For a start we used this plugin as a base,
We added a textbox and a submit button on their html page on the click of which it captures an image, takes the string from the textbox and inserts it in the image exif data. We are now adapting our ios app to not use the web api to trigger the image capture, instead use the endpoint from our plugin and send it a string which will take the photo as well as insert the string as imagedescription in the image exif. The ios app will also send this metadata along with this string to our server. Later when user uploads the images from their pc, we can extract exif data, match it with the records in our db and map it to the correct record accordingly.
Thank you