QUOTE Doug when you say you used house wiring did you use 1.5mm wire or 2.5mm wire and did the metal case come from the French site as well as the other items
Can't see any reference to this at all??
However there is a serious side to all this - You're dealing with 230 volt ac mains power which will kill you.
Therefore there is the requirement to ensure the transformer/s are cased and if a metal case is used an effective earth is provided to the casing.
Use 0.75mm or 1.00mm flex for all mains wiring with core colours of Brown (Live); Blue (Neutral) and Green/Yellow (Earth) from the mains plug to the transformers connections. Keep low voltage outputs well away from any 230v supplies and cables. Also try and use different coloured wires for the low voltage side e.g. Red/Black or Yellow/Pink etc. This will prevent any miss understanding of which wiring is carrying the 230 volts. The use of a mains DPDT On/Off rocker switch inserted between the incoming mains cable and the transformers primary wiring is useful, especially if the rocker has a neon "Mains power on" indicator. such as these
Maplins Rocker Switches
Where the mains enters a metal case you will either need to grip the cable via a grommet and this also prevents the metal of the case chaffing the cable, like these
Maplins cable grommets or fit a Euro plug (Chassis plug) and a suitable Euro socket onto the lead, like these plugs
Maplins Euro Chassis Plug and matching line socket
Maplins Euro Sockets (Plugs have pins and are not live until a mating socket attaches power and of course Sockets have recpticals)