All your shrubs, even evergreen ones, will shed their leaves each year - the deciduous ones all in a go, the evergreen ones a few leaves each day through spring and summer, so if you use stones under they'll not be a low-maintenance surface. Bark chips or flakes, or cocoa shells, would allow the fallen leaves to blend in so not need clearing up.
So if the stones are a given, I would think shrubs with very large leaves easy to deal with, like magnolia or fatsia, together with shrubs with extremely fine leaves which will disappear between the stones, such as yew, tamarisk or thuja.

Strong architectural plants such as phormiums - I wouldn't use Cotswold stone though it gets green and dirty too quickly - white beach pebbles would be much more in keeping with the area and give the contemporary look you want.
You should definitely do a proper soil test before buying plants - it's quite likely that your soil will be on the chalky side.
Some of the Hebes and Lavenders could do well. Look towards the Mediterranean/Australian/South African plants that are drought tolerant.

Now you have a list to begin with what I would suggest you do is take a trip to the several Garden Centres/Nurseries that can be found in your neck of the woods,then you can put a visual to the names and possibly find some more you like.I live in Southampton and over the years have regularly visited Wimborne Market on weekends to add to my stock.I have found prices there are much more reasonable,I know Garden Centres have overheads but so do I, and mine take preference.You can get most things there,annuals,biennials,perennials,fruit trees,bulbs,etc.There is sometimes a chap there selling David Austin roses ,clipped Box for a fiver each,another grower who has a Nursery in Fordingbridge,sells ,among other plants ,15 Primula in 3inch pots,again,for a fiver.I asked him once how he does them for that price and he said he gets them sent over from Holland and grows them on.I wish the internet was about when I started gardening,such a hive of information,good hunting.PS,do you know if they have done anything with the TG Hughs site in Boscombe yet?regards,kerryvw.