You can only call non-UK EU/EEA numbers when you are roaming outside the UK. You are not roaming in the UK.
In the UK, goodybags include calls and texts to UK landline numbers starting 01, 02 or 03, UK mobile numbers starting 071, 072, 073, 074, 075, 077, 078 or 079, voicemail (443) and mobile data.
Elsewhere in the EU/EEA with Roam Like At Home enabled your goodybag also includes calls and texts to any EU/EEA landline or mobile number (conditions apply)
Goodybags never include:
Calls or texts to international numbers from the UK
Calls or texts to Non-UK numbers starting 01, 02 or 07 (e.g. Isle of Man or Channel Isles)
Calls or texts to UK numbers starting 070 which are not mobile numbers
Calls or texts to numbers starting 084, 087, 09 or 118
Calls or texts to 5 digit short code numbers
Video calls to non-giffgaff numbers
Calls to 101 (Police non-emergency number)
Using your phone elsewhere in the EU/EEA if you do not qualify for 'Roam Like At Home'
Using your phone whilst outside the EU/EEA;
for which you need PAYG credit
This guide should help you understand how you will be charged for a call, text or mobile data wherever you are in the world.