The identifiers I've been using for Scratch Bank 1 in HotPaw Basic are:
380 service$ = "A495FF20-C5B1-4B44-B512-1370F02D74DE"
390 charact$ = "A495FF21-C5B1-4B44-B512-1370F02D74DE"
400 rem FF21 for Scratch Bank 1, FF22 for 2, etc. up to 5
Look for a NON-Bean iOS example app on how to set up notifications for these characteristics using just Core Bluetooth (there are some fairly simple Core Bluetooth heart rate monitor source code examples/tutorials out there). The Bean SDK traps the Core Bluetooth delegate callbacks for characteristic notifications so that an iOS app can't use them directly. So my iOS apps connect using Core Bluetooth directly, ignoring the Bean SDK, to get Bean Scratch bank characteristic update notifications.