ReferenceError: Can't find variable: FileTransfer

I have the following plugins installed
com.googlemaps.ios 1.13.0 "Google Map iOS SDK for Cordova"
cordova-plugin-camera 2.2.0 "Camera"
cordova-plugin-compat 1.0.0 "Compat"
cordova-plugin-device 1.1.2 "Device"
cordova-plugin-dialogs 1.2.1 "Notification"
cordova-plugin-email-composer 0.8.3 "EmailComposer"
cordova-plugin-file 4.2.0 "File"
cordova-plugin-file-transfer 1.5.1 "File Transfer"
cordova-plugin-geolocation 2.2.0 "Geolocation"
cordova-plugin-inappbrowser 1.4.0 "InAppBrowser"
cordova-plugin-insomnia 4.2.0 "Insomnia (prevent screen sleep)"
cordova-plugin-network-information 1.2.1 "Network Information"
cordova-plugin-splashscreen 3.2.2 "Splashscreen"
cordova-plugin-whitelist 1.2.2 "Whitelist"

App is falling over on
var ft = new FileTransfer();
Error = ReferenceError: Can't find variable: FileTransfer

Also fails on: console.log(FileTransfer);

window.resolveLocalFileSystemURI(filePathAndName, function(fileEntry) {
... is working OK.

XCode is reporting this warning during build:
/Plugins/cordova-plugin-file-transfer/CDVFileTransfer.m:224:34: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead
Otherwise the build is clean.

I tried removing & re-adding the file-transfer plugin many times.
On installing the plugin I always get this error .. (but I doubt this is causing my reference error issue)
Installing "cordova-plugin-compat" for www
Failed to install 'cordova-plugin-compat':AssertionError: path must be a string
at Module.require (module.js:362:3)