|Copper spacer in place ready for mounting
What to do? A quick solution was to place two large flat washers on which would allow the pump to sit flat and square, as well as, being able to slide in and out as I adjust the belt for tension.
The washers were the ideal size, but a better solution was available with a little cooper stock.
This means now, that any Sherwood pump I buy to replace, now no longer needs machining to fit the mounting bracket.