HI
I am a software developer with over 7 years of experience and 2 of those are in the UK. Please refer to my profile for more information.
I can can help you with your task with a bit more increased budget (150 USD + freelancer fee). You have to create the milestone before starting the project and you can release it once the work is done (Please refer to Freelancer help on how to do that).
According to the description and the budget what you need is an app built with cordova or similar platform to support both, or if your device is Android I can build you an Android app which is much more fast and reliable and could be completed in a couple of days(and with less budget).
As I understand the App is to be run on your device offline (most of the time) and the customer or you are going to pick the device up and use it to enter the details.
Looking forward to hearing your thoughts on this.
Cheers,
Saminda