In all the fuel injection installations I have ever been involved with we have always mounted the high pressure pump as low as possible (basically level with the bottom of the tank) with the shortest inlet pipe possible & have used the head of fuel to feed the pump. Predominantly the pump used was the Bosch 044 and they pump rather than suck so need the head of fuel to draw from.

In your case Corky I'd look at fitting an in tank pump especially with the way you have configured the top of your fuel tank. I'll email you a picture of a solution.
Alternatively drill a hole down low in the side of the tank, fit a bulkhead fitting & a short alloy pick up pipe to the bottom of the tank & this could allow you to run the external system you have fitted.

As Paul says, a second skin of aluminium on the rear bulkhead with a 1" insulator sandwiched between the skins will help keep the noise & the heat out of the passenger area.