A British Airways business class passenger found his seat similarly soaked and BA offered 40,000 Avios as compensation.
Compensation ought to be the full cost of the ticket at a minimum. British Airways may believe that 40,000 points is generous, that all they promise is transportation from point A and point B (never mind that this was business class). However I believe that they promise transportation from point A to point B free of urine and they failed to deliver what the customer paid for.