Sounds as though it was expensive ...

Yes, they are more expensive than non-integrated machines. In compensation,
at least they are usually well specced. Basically, you have to pay extra for
integrated, but are forced to do this to an already good model.

Yes. They are correctly designed with airflow in mind. They give various
options in terms of vent sizing and positioning. They've thought it all
out.

Even cleaning the heat exchangers?

That's not something I've ever needed to do on a fridge/freezer. You could
always undo the bolts and lift it out if you really want to dust the back.

They can be pulled out
from under the worktop like a freestanding appliance and aren't bolted in
place at all.

So they're not built in. Just covered at the front.

Correct.

I know a large kitchen like that. I had to open many doors to get to what
I
wanted. The door manufacturers have done a good job persuading consumers
that their appliances are something to be ashamed about :-)

Once you've accumulated a full range of appliances, your kitchen would look
like a branch of Comet unless you found some way of hiding them. Not
everyone has room for a utility room where the appearance matters less than
a kitchen.

I will have one non-integrated appliance, though. When the kitchen is
finally complete, it will have a nice range style cooker to go into the
fireplace. (Not an always-on Aga, but the conventional gas version
Rangemaster Classic 90).

Christian.