Octopussy - did they offer you compensation? Regulation 261/2004 provides
2. If an operating air carrier places a passenger in a class lower than that for which the ticket was purchased, it shall within seven days, by the means provided for in Article 7(3), reimburse
(a) 30 % of the price of the ticket for all flights of 1 500 kilo- metres or less, or
(b) 50 % of the price of the ticket for all intra-Community flights of more than 1500 kilometres, except flights between the European territory of the Member States and the French overseas departments, and for all other flights between 1 500 and 3 500 kilometres, or
(c) 75 % of the price of the ticket for all flights not falling under (a) or (b), including flights between the European territory of the Member States and the French overseas departments.
I'd say they owe you 75% of the price of the ticket (i.e. what you paid including the upgrade).
Your colleagues should have been composted as well, for being bumped.
Remember that the Regulation applies to all flights from the EU (including US carriers), and Switzerland/NO/IS