Re: never seems to taste the same?
"kettle is a resistive load so doesn't need overload protection"
Some electrician you were! Overload protection on a circuit is to protect the cabling, not the appliance(s) at the end of it. Ditto short circuit protection. Maybe you were thinking of over-voltage protection as used on industrial motors?
The 50V "touch voltage" (not a technical term in the U.K. Regs) is the maximum voltage the CPC (earth wire in common parlance) or neutral is allowed to reach by design under fault conditions in a domestic installation.
It is derived from the typical surface resistance of human skin and the typical current required for a shock to be fatal to a human (many other animals are much more sensitive). Current kills you, not voltage (hence we don't die from a bit of static, unlike MOSFETs).