Anyone know where I can obtain ArchCad19 UK Template? I expected to find it in MyArchicad.com/ profile/my products, but it's not there.
It is always better to create your own template.
Generic templates are only as good as people that created them and, unfortunately, contain errors, omissions and inconsistencies.
Taking into account UK government's excellent support for BIM in a form of NBS web sites, BS, PAS1192 and other Common Data Environment-related documentation, creating your own template might be a much better way to go.