I am looking to buy a fully integrated fridge for a new fitted kitchen.
Been on the B&Q website as follows and am slightly confused at whether
these products are suitable: http://tinyurl.com/yx6bka

Some are "built-under" (which I thought meant that it fits under the
worktop but you cannot add an appliance door to the front), and some
are "built-in" (which I thought would be fully integrated).

Looking at the cheapest option which is the "Built-Under Fridge Model
RLA600 White", the dimensions are H 816-868mm x W 596mm x D 550mm.
Since the depth is only 550mm, wouldn't this also be suitable as fully
integrated with an appliance door? And can a plinth also be used in
front of this appliance?

Also, what is the difference between a larder fridge and a normal
fridge?