@BandOfBrothers I took it in to town and couldn't connect to 5g despite whitelisting. Turns out my Vodafone plan is 2 years old and 4g only. I borrowed my son's Vodafone sim card and 5g worked perfectly. Seems VOLTE is ok as well.
Just as a footnote, I managed to activate the Hong Kong Samsung Pay, add my Nationwide UK card and it works perfectly. Also works with my Galaxy watch 3.