Terrible fire and feel sorry for people arriving back from their holidays to find their car destroyed. Apparently there were no sprinklers in the car park, but even if there were I don't think they would have been of any help.
At the moment although it is mainly speculation, it seems that the vehicle that started the fire looks like a Range Rover or Discovery however some sources are stating it was a diesel vehicle. Looking at the video of the fire it seems that the fire was too intense for it to be a diesel vehicle which casts doubts if it was a diesel? Using diesel to start a fire is very difficult. See https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-67077996
At the moment although it is mainly speculation, it seems that the vehicle that started the fire looks like a Range Rover or Discovery however some sources are stating it was a diesel vehicle. Looking at the video of the fire it seems that the fire was too intense for it to be a diesel vehicle which casts doubts if it was a diesel? Using diesel to start a fire is very difficult. See https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-67077996