I think the problem is going to be with the waste water pipe. This will be a thick rubber hose. As the probs started after changing your kitchen, pull out the d/wr and see if this hose is kinked or squashed, for example under or behind the dishwasher or adjoining appliances. If not, look at its run all the way to the drain (you may need a torch).
In the UK, we usually have the drain hose poked loosely down the end of an upstand pipe, or else pushed onto a spigot at the sink outlet trap. If you can't find any kinking or squashing, pull the hose out and fasten it so it empties into your sink, then give the dishwasher a rinse cycle. You ought to see the water being pumped out of the hose into the sink. If you don't then either the pump has stopped working, or the hose is blocked.
If the hose-into-the-sink method works, then have another look at the drain the hose was formerly connected to. See if the spigot or drain is blocked. Also, new spigots are supplied with a closed end, which you have to cut off to open them and to fit your hose.
Tips:
1) As soon as you detach your drain hose, water will start to run out by gravity as soon as it is lower than the water level in the dishwasher. Put the end into a bucket.
2) To push your dishwasher back into place without trapping the hoses or cables, use a stick or something (I use a disabled person's Helping Hand) to hold them out of the way.
Edited to say - you say the dishes are left dirty? do you mean that they still have the food on them, as if there has been no water squirted over them? If this is the case, it may be your pump has stopped working. If you are lucky this might be simple like a wire has become detached, but a new pump can be fitted by a service engineer at reasonable cost (I would have thought less than 100 Euros) But make sure it isn't the drain hose first.
