Not to be rude, but do you have a repair manual?
The reason I ask is that some folks (me included) dont know what is different in your Ghia from us. Plus there are not a lot of older foxes in here (lookin at the total number of people who post) so info might be scarce.
On a fox, the fuel filter is kind of above the axle, but with your carb set up, i would think it is located elsewhere (engine compartment maybe).
Good luck.