Difficulty in reading ios push notification payload from FCM

I’m Just setting up push notifications for my app. They’ve been working welll on android for months and they display a toast when they come in while the app is open. I’ve been trying to enable them on ios and they’re coming through in the background perfectly but when the app is open I can’t read the content of the message. The payload I’m receiving is this:

{"google.c.a.c_l":"notification","google.c.a.e":"1","aps":{"alert":"local"},"gcm.n.e":"1","google.c.a.c_id":"63900123618947024","google.c.a.udt":"0","gcm.message_id":"0:1535060571041708%93cc4aea93cc4aea","google.c.a.ts":"1535060570","tap":false}

My guess is that the content is somehow stored in the gcm.message_id but I don’t know how to access this. It seems like something that should be straight forward but I can’t for the life of me figure it out!

Any help would be amazing. Thanks in advance.