<p>I have made a temperature ⨉ fan speed tower which needed 3x9-1 ChangeAtZ post processing scripts and it took me quite much time to configure them all (and check it twice). Is there a way to save this, so that I wouldn't need to make them all again if something went wrong and I needed to start over or if I wanted to do something similar again ?</p>

The UK uses 230 V mains voltage. The 220 V designation is from the past, Europe is now using 230 V. You do not have to worry about the frequency.
You should place the switch to 220 V and plug the cord into the socket. The printer should start immediately booting (cycling) the printer firmware, the LCD should light up and the cold end cooling fan will spin (annoyingly).
If nothing happens, you need to check the Power Supply Unit (PSU) and all cables for proper connection (does the fan of the PSU spin if it has one, you should at least see a led light up). A multimeter is not expensive and generally very valuable to test if it outputs 12 V. That way you know the PSU is working or not, if it works the problem is at the main printer board.
As these PSU's are pretty cheap and faulty, you could well have received a broken one.
How to measure the voltage?
If you look at the connection terminals you will find labels above them. Measuring position 6 and 8 might be the incorrect ones, this depends on your PSU. If you have exactly the same PSU as from the linked video, measuring between 6 and 8 would be correct:
From the image above the connections from left to right (for other PSU units, the order may be different, I have units where the connection to the mains is on the right):
```
L
```
,
```
N
```
and
```
ground
```
are used for connection to the mains,
```
COM
```
(stands for common or 0 V) or sometimes denoted as
```
-V
```
is the output ground (negative, connection for the black wires) and
```
+V
```
is positive, connection for the red wires.
You need to measure the voltage difference over
```
COM
```
and
```
+V
```
, this should be the voltage of the power supply. Ideally you measure the voltage when the power supply is delivering a load (e.g. directly connected to a strip of LEDs or directly connected to the heated bed; some faulty PSU crash in under load, this can be seen by a lower voltage than the rated voltage).
If the PSU is correctly wired, your fuse is not broken, does not have a LED lighted and the voltage is zero the unit is defective.