Well I guess that I should have done more homework before my OP.
The tyres are now off my alloys, and the rims are actually 14x7 inches.
THE BACKSPACE IS 3 & 5/8 inches.
Not sure whether the rims being one inch wider changes my original question, or not??
Sorry if I have confused anyone
I don't know how it's done in Australia (I'm assuming the same as here) but here wheel widths are measured inside bead to bead. and your alloys are then about 8" overall width.
So your alloys are a little deep dish (expected) , because a zero offset wheel would have a bs of 4"
So, I would recommend the smallest 60s aspect ratio that are appropriate for a 7" wheel.
I'd suggest a 215/60x14 all around, or 225/60 in the rear only.