For cebeo you need a VAT number. If that’s a problem for you (you don’t know anyone with a VAT number willing to order them for you), you can try contacting gigatek.be, they are a cebeo reseller. I see they have the fuses for sale on the website, but the fuse holders not, but if you ask them they’ll probably order them for you as well…
I paid 37 euro per box of three fuses, and 132 euro per 3p fuse holder (vat incl.)
I used the thermal camera for peace of mind, but it wasn’t necessary, nothing went higher than 30 degrees celcius or so. I imagine if you follow proper design rules (good quality components, sufficient cable thickness, …), crimp the terminal lugs well, and torque the bolts correctly, you shouldn’t have any issues.