Connecting three led transformers
A 250V 10A switch is standard for light switches in those countries that use 230V mains. It should be suitable to put inline on either side of the power supply (which is what you will have for LED lights - in contains a transformer but has other stuff as well).

The voltage on the LED side will be much less than mains voltage and the current on the line side will be much less than 2.5A or even 3x2.5A for all 3

It is likely that the LED voltage will be DC, not AC and, in general switches have a lower current rating for DC than AC and may be unsuitable. If you change your mind and intend to put the switch on the LED side, check the switches DC capacity.