Hello to all

30 days before travel to Jamaica, the lead passenger has cancelled our holiday, leaving me £1200 out of pocket, this was done without my knowledge and agreement, even though I asked if i could buy out her side of the holiday and take my son Thompson have refunded I believe £50,
I would appreciate any advice, I wish to pursue a claim against the lead passenger through a small claims court, does anyone have any experience on the matter, and if it is likely to be successful, its not so much about the money more the principle

Any advise appreciated