If there is camera footage (many trains don't have cameras), then the police will have to look at it, but don't count on them to have time. File your police report anyway; you will need it for your insurance.

What accommodation did you have? Seat, couchette or sleeper? In case of a seat, compartment or open plan?

Thank you. It was an open plan seat in 1st class

Some general advice, from experience, do: store valuable documents, digital devices and medication in your hand luggage, never in your 'hold' luggage; sit in a seat that offers a view of your hold luggage, if possible; use relatively tatty and unattactive looking hold luggage; personalise your hold luggage, to make it clearly yours; use any locks to secure zips etc; use wire/chain combination locks, to secure hold luggage to racks; place your hold bags in racks, so as to make theft difficult; consider including electronic tracker tags in your hold bags.