Android Question B4A to B4I conversion

Difficult to answer you, depends of your B4A code (if you used XUI) and the libs you used, I can give you an estimate but I need to see your project
There is a learning curve as well, and a different life cycle of an App on iOS (here it's depend of your skills)

I did some Apps migrations, usually you need to rewrite and refactor some part of the B4A code, not mandatory, you can can create another dedicated iOS App, but it's better to maintain the two projects easily

Thanks for the response. Here is a link to the App ( https://play.google.com/store/apps/details?id=com.BOBs.BBS )

I guess I should learn the iOS life cycle (compared to the Android life cycle) and start converting some of the code to use XUI where possible

Thanks for your help

You may have a look at the B4i Beginner's Guide. Chapter 11 Differences B4i <> B4A.
And in the B4X BasicLanguage Booklet chapter 3 Program flow / Process life cycle.