Built-in Fridge freezer

[LIZS]

It looks like our Neff fridge freezer has given up . It is a FD7406 I think , over 15 years old. Lots of noise intermittently but not cool. How do you determine a suitable sized replacement, do you measure the outer doors, the space or the appliance itself ?

anyone ? And why are integrated ones so much more £££

ah and apparently there are 2 sorts - fixed door or sliders. Typically we have the sort with fewer more £££ models , was quoted £699 today