Sort issue with 1,1a,2,2a,2b etc

Hello,
i did post on another forum but the results didnt work and i could post file, so hoping i am hoping i can post file here and someone can fix issue.

I am trying to sort my rows in numerical order but 4 columns marked Aisle bay shelf Bin in my bin column i have numbers like 1a 1b 1c , when i sort it drops them to the end of rows i want them all in order.

i have formulas in those cells that need to stay as it reads from different columns.

Does anyone know how this can be done i have attached the file
Hope this works.

Darren