There are many different names and brands. I always had PCL19 which we all know as standard PCL. I converted to PCL XF which cost me a fortune. Screwfix is the cheapest place that you can go and collect. I did a bulk order with a supplier and got some good prices. One thing I would say I've noticed about PCL XF is in static situation sometime they need a quick twist or they can bleed a little. Never noticed that the PCL19 The probes cost pennies and there is a difference in buying PCL compared to the cheap one. The PCL XF style is often referred to as a Euro but technically a Euro is a different fitting. The Prevost couplings you mention are really nice, they are expensive but from a safety point of view they are the best. PCL19 is probably the most common out there, I have convertors both ways which can be a simple as PCL coupling with a PCL XF probe screwed in it. I also have a short hoses with conversions on.