Dear Justinho
Even though you intend using only 13 amps in your garage, subsequent owners/users of the property will be unaware of your bespoke electrical setup, and may therefore overload your spur. This is why you need to convert your garage (very simply) to a ring circuit. All your new...
remove the bottom section, thoroughly clean the threads with your wife's toothbrush. wind with ptfe tape . replace as tight as you can, then man up and give one extra quarter turn. finally, always ignore the advice of professional plumbers and electricians, they live to make simple tasks appear...