Update.

I got a reply with apologies, a sort of explanation about pre-ordering standards - but not what exactly went wrong in this case - and 4500 avios "To apologise for what happened and to show you how much we appreciate your support" even if I didn't ask or even hint about compensation when I wrote to CS.

To me is enough if they make sure for the future to not mess up pre-orders when changing menu and courses

PS
Globaliser: do you think the glitch was the system selecting automatically the next course in the list when the chosen one was withdrawn/no longer available?