I think it does mean there are 3 Section 7's, but I stand to be corrected!
1 West, 1 East (new, as you said), then 1 Central.
I took aerial views with me one day and tried my best to mark as many of the sections in their correct place. Once I got the maps home of course, all the scribbles which made perfect sense at the time, made not quite so much sense.
When looking at the whole cemetery on an aerial view, the part down towards the river is certainly 'central' in position.
Perhaps Section 7 West has 3 parts to it - A, B, & C? It does stretch along quite a length.
Anne