Also there is solid 1 mm² TPS with 1.5 mm² stranded earth floating about.
That's odd. Over here it's the other way around, i.e. the earth conductor is reduced size compared to the L/N conductors. 1.5 sq. mm T&E has a 1.0 earth, 2.5 T&E has 1.5 earth, etc. The exception is for the smallest T&E, which has 1.0 sq. mm for L/N and earth.
