I have an extension cable (one bought from argos without the end connector)
which I want to connect to the master socket. It has 5 wires which arent
colour coded the standard way. They are :

White,
Green,
Blue,
Reddish Orange

Now I understand I need to connect 3 of these wires to connection 2, 3 and
5. Normally these would be :

Blue/white stripes-----Terminal 2.
Orange/white ----- Terminal 3.
White/Blue stripes---- Terminal 5.

anyone know what the white, green, blue, reddish orange wires correspond to
in the normal cable colour standard ?

I have done
blue ---- 2
reddish orange --- 3
white ----- 5

with no luck

Obviously I can try all combinations but it would be time consuming, hence
the question here.

any help appreciated

correction : It has FOUR wires (not five)