Nasty looking spot under car.

[Jimbo Bob]

I thought a small animal had died in my garage over the winter but was horrified when I found the smell emanating from my Esprit. On investigation I found a mouse nest in the rear bumber of the car. 

There was another nasty spot on the garage floor directly below two (drain?) holes that lie just rear of the larger fuel tank inspection hole. Poking a screwdriver in them it appears that there is foam in them and possibly another mouse nest. How do I access this area? Its not part of the fuel tank area. I can't see anything from the engine bay.

The spot on the floor is new and doesn't appear to be oil, coolant or brake fluid.

 

1983 S3. Esprit n.a.