Thank you for posting here in Apple Support Communities, PoppyGoose.
We understand that you've been experiencing issues downloading apps onto your iPhone, and we'd be happy to help. To start, can you tell us if you're currently using iOS 10.3.4? If not, we ask that you do so: Update your iPhone, iPad, or iPod touch
If updating the iOS software doesn't help, we ask that you check to see if the date and time settings on your iPhone are set up correctly: Set the date and time on iPhone
Lastly, we recommend that you reset your iPhone's location settings by going into Settings > General > Reset > Reset Location & Privacy: About privacy and Location Services in iOS and iPadOS
Keep us posted on the results.
Update your iPhone 5 to resume using App Store, iCloud, email, web, and other services
Cheers!