I would not fit one of these, internally the link wires are not big enough for the 60A or 100A UK domestic supply regardless of what the writing on the unit or the spec says. Wiring it wrong and releasing the smoke early make be a lucky break.
No, the braided wires on the ones I have seen when opened up which carry the load. There are lots of makers so at least some are under sizing those wires and not buying two to open one to check.
Hm, that's standard procedure for me?! Those are safety relevant devices and by "saving" on the cost of a professional by DIY-ing I'm more than able to afford two of whatever it is I'm going to install - one for analysis to make sure the stuff works as expected.