Commando is a model name for some MK products and I am not sure if they are marketed in Greece. I am sure you would get an equivalent from Kafkas
. Print off a picture and the specification of the plug/socket you want from somewhere like Amazon or RS Components
and take it into the shop. They are usually pretty helpful. The shop is on the Chania - Kissamos old road going out of Chania. From the junction with the Omalos road go up the hill and through the first traffic lights. Kafkas is on the right hand side at the brow of the hill just before a Silk petrol station. If you get as far as AB Supermarket you have gone too far.
Cable is usually rated to prevent it catching fire and that depends on how it is installed. For your 10 A load 2.5 mm should be OK. It's rated at 13.5 A even installed in an insulated stud wall and much higher than that in free air.
The voltage drop down 50 m of 2.5 mm cable for a 10 A load would be about 3.7 V or less than 2 %. I wouldn't have expected that to cause a problem although it might be worth checking what your actual voltage is at a socket in the house. Some people out in the country at the end of long lines can have quite a bit less than 230 V at the distribution board and then an additional 3.7 V drop might be a problem. Resistive loads, like a hob or an oven, draw less current if the voltage drops and so simply heat up more slowly. Motors, however, tend to attempt to drive their rated load so if the voltage is low they can take higher current and that can cause the windings to burn out.