After building up the first PCB for testing the design, I have found an error in my design in that my switching loop is too large. I sort-of expected this but wanted to test the design to find out for sure. For the testing PCB, I have tacked on extra filtering capacitors as well which has helped slightly as I initially completely mind-blanked on installing ceramic filter capacitors.

I will be revising the design of the PCB to amend these issues soon.

That all said, the unit does work well at 4A output current, regulates well, and charges the battery quite nicely. But just runs hotter than expected. I will be testing efficiency in the coming days when I have more time to sit down with the unit.