Here is an old ad on Ebay.co.uk showing a variety of interesting Terry's accessories.
I am curious about a couple of things.
1/The 'Slimming Device' is a short-spring chest expander.
It may have been intended for women, judging by the name.
I posted a home-made version earlier in the Iron Horseshoe thread that can have up to 5 springs.
2/ The wall pulley has a spring at the fixed end then a device for connecting two springs.
I wonder why the first spring was there. You don't need it.
I have a couple of similar devices to the connector from Weider- but they screw directly into a stud in the wall.
It is an essential part of my workout, for forward presses with feet in the corner for the suspension trainer effect or the more usual split stance;
also for standing rows; straight-arm pulldowns, triceps pressdowns.
one-arm flys, woodchoppers and so on.
Though you could heat and bend thick wire in a vice into a useful shape,
I think a piece of flat steel, either rectangular with 3 holes in a triangular configuration or with a bit more work cut in a triangle with a hole drilled in each corner and some biners would be an easy replacement for this.
Perhaps you could use a modified part of a strong door or gate latch.
Another easier solution would be to use regular eyebolts, which are available at any hardware store, and biners.
You could double your load capacity with 2 attachments screwed into parallel studs
Or, you could get one (or two) of these bungee jumping webbing attachments and use it as is or with biners: