Ok, so pretty much as soon as I posted the question the answer came to me - but it might be useful for others. In the web address part for the distribution I was entering the address of the page where the link was (ie https://www.example.com/my_app.html) - NOT where the .ipa file was! https://www.example.com/my_app.ipa All working correctly now.

Aargh! Thanks. I swear curly braces will be the end of me one day!

Thanks, yes that works and is exactly what I was looking for. I had looked at filter but could never work out a way to implement it for what I wanted (I've only been back at coding for 6 months or so, still getting my head around things)

Update here is the code: import SwiftUI struct CurrencyList: View {     @EnvironmentObject var FetchedRates:FetchRates          // Info : FetchedRates.faves = ["AUD", "BGN", "CNY", "GBP"] //     @Environment(\.managedObjectContext) private var viewContext          @FetchRequest(         entity: CURRENCIES.entity(),         sortDescriptors: [             NSSortDescriptor(keyPath: \CURRENCIES.core_Country, ascending: true)         ])          var items: FetchedResultsCURRENCIES     @State var showFavs = false          var body: some View {         VStack{             HStack{                 Toggle("Favourites only", isOn: $showFavs)                              }             Divider()                      }                  List {             ForEach(items) { record in                                  HStack{                     VStack{                         if FetchedRates.faves.contains(record.core_Code) && showFavs == true {                             HStack{                                 Text(record.core_Country)                                                                  Spacer()                             }                             HStack(alignment: .center){                                 Text(FLAGCODES[record.core_Code] ?? "")                                                                  Text(record.core_Code)                                                                  Text(record.core_Currency_Name)                                                                  NavigationLink(destination: CurrencyDetail2(RowData: record)) {                                                                      }                             }                         }                         else{                                                      }                     }                 }                 .frame(height: 50)             }         }                  .navigationBarTitle(Text("Exchange Rates"), displayMode: .inline)         .listStyle(DefaultListStyle())         .navigationBarItems(trailing:                                 Image(systemName:"antenna.radiowaves.left.and.right").resizable()                                 .foregroundColor(FetchedRates.dataStatus))     } } So basically output of the list is only the currencies within the array of FetchedRates.faves ["AUD","BGN","CNY","GBR"] which is what should happen, but the list has large gaps in it where other currencies which aren't favourited would normally be.

I would start off with the '100 days of swift course' (google it) - a little bit of Swift every day for 100 days. And it's totally free. I have learned a lot from that site over the past couple of years. On the site are numerous "how-to's" so that when you get started on your own projects then get stuck you can use it as a quick reference. Want an example of how to do a list in iOS ? its there! etc. But as mentioned above, make use of as many resources as you can. All will explain things in slightly different ways and it may just 'stick' better explained in a different way from a different site.

Should have added - the error I currently get with the code show above is "Cannot convert value of type 'Flight.Type' to expected argument type 'Flight'" on the Navigation link of the FlightView. If trying to use the EnvironmentObject I tend to get error "Trailing closure passed to parameter of type 'HorizontalAlignment' that does not accept a closure"