Hi @Samfraeer,
Thanks for your post, and a warm welcome to our Community Forum.
I'm sorry to hear you're having problems with 5G connectivity. Unfortunately, 5G isn't enabled at all signal masses, and our recent network migration to the O2 network means the connectivity in some areas may now be different.
Can you please head to our Coverage Checker and select "Existing deal", to check the coverage in your area? Have you tried to reboot the phone, and tried the SIM in an alternative handset?
Cheers,