with lighting cable on the sockets and skirting on the worktop do you think the kitchen drawing was scaled wrong ? easy mistake to make.
TBH over the years i think i've come across the use of smaller cables being used the most incorrectly, perhaps if the sheds only sold 2.5 and up and done away with the smaller sizes may half the amount of bodges they do.
Maybe the shed only had 2.5mm T&E in stock, which is why the installer went for the 1mm flex