Vinyl Click ‐ Under or around shower tray?

[Coliander]

So, I've (hopefully) just about finished the plumbing in my bathroom renovation and it's almost time to reinstall the floor.
I understand that when tiling, best practice is to tile the entire area and then locate the shower tray on top of the tiles, but what is the best solution for vinyl click flooring?
Should I install the shower tray over the vinyl click, or would it be better to lay the vinyl after the tray has been installed? What about the WC and basin?
The shower tray is 50mm low profile and I plan on installing it directly to the floor.

Also, as I'm replacing the entire subfloor with fresh 22mm chipboard, am I right in thinking that a ply lining won't be necessary?

Ta!

 

[flameport]

Shower tray in first, as the whole thing has to be properly supported underneath to avoid movement and cracking.
They never go over tiles or any other finished floor covering.
Toilet and basin can go in afterwards which will make fitting the floor easier as it won't need to be cut around them.

Chipboard is a poor choice in a bathroom, as it will be destroyed when it gets wet. A plywood floor would be a much better and longer lasting choice.

 

[Coliander]

Thanks for the clarification!

Re: chipboard subfloor. I will be going over the 22mm chipboard with a layer of 9mm ply, then sealing the gaps/seams with acoustic sealant before installing the tray. That should keep things relatively dry underneath should the worst happen!