PayPal had to go through a "are you who you say you are" procedure, whereby they sent a code to either my Mobile Number, or Home Phone.
Entered the code on the PayPal website and clicked "continue" - whereby nothing happened! Click, click, click - nothing.
Turned off Firewall & AV, tried again. Same problem. Click, click, click.
Emailed your link to my iPhone. Signed in. Paid via PayPal, no problem! FFS.
It's ordered now. Thanks for your help.