The first time I replaced this switch I struggled for a couple hours before I found the right tool (a jeweller screwdriver is not the right tool). The second time I had to replace this switch, it literally took 10 minutes and was SOOOOO.... easy. All you need is the correct tool. No need to remove the seat or be a super contortionist. One screw is plainly visible and the second you find by feel, but with this "special" tool, it's easy to find.
I bet you already have this tool.