Thanks @Sujan12 I found a post on stackoverflow with a video which explained a way to use xcode - apparently I needed to click on the project name in the left hand pannel which lists all the errors/warnings. It then displayed the options to edit.
Building on ios was not an issue (apart from wondering why the resources icon image had to be 1024 x 1024 rather than 192 x 192). The problem is that once built the app requires the certificate and signing to run on an actual device.
Thanks @reedrichards yes finally got round the issue - the problem is that I am not familiar with the Apple system so when it said click on the project name - I was clicking on the wrong object.