What exhaust do I need?

Someone changed the engine in my 1970 IIA lwb for a 2.5na diesel, but made an utter bodge of the exhaust, which I'm now trying to sort out.

I've got a 4cyl front pipe, adapted to fit a 2.5na manifold. However, the rest of the lwb exhaust which came with it looks like it's for a 109 with a front fill tank:

What bits do I need to sort this out? The Paddocks site offers a lot of confusing options!

Here are the bits I've got already:



My tank is rear fill, if my last post doesn't make that clear.