GW , I understand your leak. There a was a problem with the original BX 2200's with a tank issue I learned on here and I asked about it. I was told mine was OK.
Then after 2 years I developed a fuel leak if I filled the tank up.. Same as you said on the left side. I was pissed.
Because the tractor was running rough I had changed one fuel filter and it smoothed out..
And, then one day on here, I found out I had another fuel filter under the middle of the tractor. I got under and changed it and then realized I did not have a leak anymore when filling past half tank.. Never had the leak problem again...
You may have a real leak but a cheap attempt to try is to change both filters and see what happens..
Worked for me..
Thanks,
Tom