Hello Swedish Pride from another Swede...
Lot of guys have had success with those inexpensive controls. Keep in mind, though, it is what you'd call a cheap Chinese import, and those things (of all types) can be hit or miss. They either work spectacularly well for a crazy low price, or the magic smoke makes an exit the moment you power it on. Hope you get the first.
Your 230 VAC 20A line can in theory deliver 4.6 kilowatts, MORE than enough for your boil. The controller is rated at 3 kilowatts. So if your heating element is genuinely a 230VAC 2.2KW, it should be fine, you have 800 watts of overhead. These things don't like to be run full bore, full rated, all the time, as they will get hot.
Since you are running off of a standard line there, I'd get a decent (but common) switch rated 230/20A that lets you bypass the controller. Flip the switch, controller is out of the circuit, and your mains supply the juice to the element. When it's time to
control, switch her back into the circuit and dial it down as needed.
Watch/feel for heat the first few runs. You can mount it such that the Al casing is attached to a larger metallic mass to act as a heat sink. I'd also carefully test that large aluminum case to make sure it doesn't become electrically hot due to factory (or user) error; ground everything as needed.
Lots 'o babbling from the BigSwede, I think your setup will work fine. Oh yes, it's nice to have a voltmeter or ammeter in there somewhere, lets you be repeatable. A cheap analog VM will set you back 5 Euro/whatever, they aren't much.