The WG, and possible UK Government have a habit of making minor tweaks to the regulations. You are quite right, you can meet up with 1 pal in a public place. How long that has been in force for, I am not sure, but almost certainly not before the last 3 weekly change.
Personally I think UK government have been appalling and given everything, Wales and Scotland have been better over this this pandemic. UK deaths have risen last 2 days. We are far from beating this virus.