A shame about your hatch
, it sounds expensive.
It is probably not a problem with the sunbrella. Although a dark colour, sunbrella is a fully breathable fabric
unless the one used has a rubber-ish or polyurethane
backing (Seamark or Sunplus). The darker colours still get hot, but air circulation means there shouldnt be damage to the surface underneath. As a marine
trimmer, I recommend a product called 303 Aero Space Cleaner, excellent cleaner for acrylics that puts a protective layer on the surface, and even has a sunscreen. Your local trim shop should stock it.
Hope this is of some help, unfortunately it wont repair existing damage