Die to distance from my home charger my regular cable is 12.5 metres long. Occasionally it will charge 5% and stop. Unplug, replug and get another 5%. With my regular yellow cable never any problem. Has anyone else had problems using other than the supplied Skoda cable.

2024 Superb PHEV.

Is this an extension cable you are using? If so, what gauge (mm2) are the cores?

Not an extension cable. A commercial EV charging cable from my type 2 home charger. 12.5Metres long.

Is it correct gauge (mm2) for the current used while charging?

Length of connecting cable can become an issue if its cross-section is too small, problem becomes worse in longer cables through increased volt drop.