Exchange fabric for enclosures with hard casing

[RebekkaML]

From Quarterly update ticket Q1 2025 #127:

"The fabric enclosing the workstation is likely to be just as heavy as a lightweight hard casing and likely to keep heat in. It also creates fibres around the workstation and cannot easily be wiped. A hard, lightweight, wipeable alternative should be sought.
Original suggestion made by PB on 25/07/2024"

This should be implemented during Q1 2025 so that the new material can be tested in summer to see whether it solves/ alleviates the heat (and fiber) problems.
Also relates to #96.