Called penis valves 

You have to shout it as well

That’s what I was expecting, but these particular ones just come screen printed on to the tap so there is nothing to swap out.

Usually has both red and blue in the bag you just use as needed

This is what you’ll need [washing machine stop 15x20](https://www.reece.com.au/product/arco-right-angle-washing-machine-stop-non-return-100812)

Installed one of these for my laundry. Very low profile so good in a tight spot like back of a cabinet. 

Only downside with this particular brand is that they don’t differentiate the hot and cold so you might need to mark it some how if you plan to keep the hot tap in play. Otherwise you could just install a cold and then cap the unused hot.

Nothing that a 3/4" to 1/2" British standard pipe adapting bush won't fix!  Slightly slower fill rate, that's all.

I sell these and you're right. 1/2" inlet 3/4" outlet. 
Modern wm cocks are all pretty small these days. You could take an m&f elbow away from the thread and tap would then be parallel to wall but the difference wouldn't be huge.

I’ll need to check but I assume the washing machine ones are 20mm outlet instead of 15mm

They have a different size fitting. Cistern cocks are 1/2 inch BSP inlet and outlet. Washing mashing machines are 1/2 inch BSP inlet and I think 3/4 outlet.

You could substitute cistern cocks for the washing machine cocks.

I’m hoping that the stop cock will save enough space to use the stacking kit I have rather than a wall mount. 

It’s a heat pump dryer, so too heavy for a standard wall mount.

They are called a "stop cock" and bunnings have several options. The ones for washing machines have a different size thread on the outlet, and are labelled as such.

If you can't get them low profile enough then the usual option is to mount the dryer higher up on a wall bracket.

This is what I would be doing as well, flush seal the ones in the way, and tee off the over sink taps.

Taps dont cause hammer, if you were a plumber you would know that

Those combos are known for causing pipe hammer

Cap off the old points and get combination ones for at that laundry tub point, won't look the prettiest but will save you doing any major plumbing work

https://www.reece.com.au/product/standard-laundry-conversion-unit-with-handles-100854?query=washing%20machine%20conversion%20taps

I shouldn’t tell you this but the best performing, best looking and lowest profile solution is Arco Machine stops from Reece with a 15BST male/female brass bend chrome plated.

I don’t think you are going to get anything that’s not going to stick out pass the washing machine as it is now you’ll still need to move it off the wall some, but you can get stop cocks that have smaller handles from any hardware store

Are you replacing the trough? We had a similar setup to you but we replaced the trough with a sink and some cabinets and deleted the washing machine taps from the wall.
The washing machine water is now fed to the sink plumbing through a side hole in the cabinets and they make caps to cover up the ugly holes (even though they are hidden by the washing machine anyway).
This allowed us to put in a bench top over the washing machine which worked great but not sure if you have space for it? It’s definitely worth doing if you do imo.

Put stops over these ones, and put splitters on the pipes supplying the laundry mixer tap underneath the laundry tub. That way all pipes are hidden too

Recommend calling a plumber for a fee they will have the solution in their van and will install it

I would like to replace these washing machine taps with shorter ones to allow me to stack a dryer on top. Is there a specific name for them or somewhere in particular to source them?