We have bought a bubble pond pump thing and went for the 24volt version for safety. The pump is hardwired to around 3m of twin core cable, at the end is a connector, identical to a Tamiya connector, bit I think they call them Molex. The transformer, that will be in the garage socket, has a tail lead around a foot long, and female plug. The only way to control the pump is the switch at the transformer socket. I did wonder if I could get a suitable IP rated outdoor switch, splice and joint the cable in the switch box, then leave the socket on, and use the switch.

Although, just on for a few hours the other day, the transformer got fairly warm. But, if is isn’t “transforming” ie, the switch is off, there will be no current/voltage flow so no heat?

Thoughts?

No current flow doesn’t mean no losses – just less losses.
You’ll still get the iron losses – how much? Probably not a lot, but depends how well designed it is.
Also depends whether it’s actually a transformer or some sort of power electronics device.

Defo transformer. It’s Hozelock, so a good brand.

Although, just on for a few hours the other day, the transformer got fairly warm.

Could be normal, could be that the pump is working hard due to a restriction caused by weed and demanding more current.

But, if is isn’t “transforming” ie, the switch is off, there will be no current/voltage flow so no heat?

As above, there will be losses due to the construction of the transformer, e.g. iron, copper and eddy currents but these shouldn’t amount to much. If the pump is disconnected then it isn’t demanding power and the copper losses will be reduced

It’s all brand new kit, clean and clear water. Just setting it up. Kind of hoping for advice re the switch though…

Get a wifi/smart switched/radio control socket where it’s plugged in.
Can get them for under a tenner. Most have a range of ~20m. Give or take.

Even something as basic as that will work. Or if you want more complicated, get a wifi one and link it into your phone/google home/apple homekit.
Loads of options, depending on what you’ve already got in the house.

Timer Shirley?
Just plug the transformer into a segment timer
No forgetting to turn it on and off.
Transformer not permanently live so less drain, but the timer will use juice, not alot though.
Keeps all the hv in pne place and no need to break the cable from the transformaer

Timer is a possibility, but only want it on when we are around. Remote socket also a good idea. Smart plugs look good too, not sure if they will pick up the Wi-Fi in the garage though.

I have smart (proper smart, Zigbee and WiFi not the radio control ones) in the garden, shed and garage. Most distant one is about 25m away on the far wall of the garage and is sending consumption and power data to the hub. Through 2 brick and 4 giprock walls. Had a couple of drop outs in the last 3 years…