Just ordered the sim from Vodafone and scheduled the switch for 06/01/2020. Only offer I noticed was €10 free credit if/when I register online or something like that... so I'll wait 'till it switches - assuming I have my sim by then, then opt in to Chat Extra and top up and register online. Just have to spend my outstanding balance with Three now, €30 odd but I'm out of bundle from midnight so I'll buy a data add-on for a fiver and knock myself out calling and texting people I never bother calling or texting until it's gone!