Any 406 diesel will be relatively economical and nice to drive if you find one that has been reasonably looked after.
I've owned 2 early 1.9's and now own a remapped 2.2 2003 SE saloon, all are super comfy and a pleasure to sit in over long distances. The 2.2 is relatively thirsty but still goes further to the gallon than my sister in laws petrol Ka and I know which I'd rather drive

The 110 can be remapped to 130-140ish and gain a few MPG's while you're at it, the 2.2 can go to around 160-170 and is a very smooth engine with enough power to get the annoying Audi out of your boot.
If you find a nice example 406 HDI I would be prepared to place a small wager on the Clio never seeing the light of day again!
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