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..

40A is a bit big, the mcb is only there to protect the cable. for a 40a mcb the cable size would need to be 6mm (cost you a fortune for what you want)

why not seach these forums (garage or outside supply brings up loads) as the question you have asked has been asked several times before.

you could start with this

although underground is best since the cable is always out of harms way.

and as for sockets unless your garge is very damp ordainairy sockets will be fine, metal clad better