G block was a single storey building with two entrances. It was used for CDT and as I recall “metal work” in the earlier school. Countersinking, drill bits, tools with funny names like “odd leg calipers”
I remember making a coat hanger , but that’s about all.
G block was also immortalised in the film clockwise with a streaker running from one door to the other with a cheering class looking on and banging the windows.