Looking into it further it seems likely that the 74 1/2 had the fuel pump located up in the trunk area, much like the newer versions. What does that bracket look like? Moss does not have a part available for those years it seems. I found another MG parts site that indicates some type of hose clamp. I also found something on the web at autocharts that there was an approved AC (US made) fuel pump approved for this model.
I think I will just drill some holes in the rear riser and mount the pump in the "conventional" location.
Problems cannot be solved at the same level of awareness that created them. Albert Einstein