Posted: 23/07/2014 at 13:31
It be a good idea to look at pics of plants/flowers online or in magazines and keep the ones you like, so you've got a 'library' when you do have time to start planting up your border. Geraniums are good, plenty of varieties and tough. Verbenas, aquilegias, irises, scabious, phlomis, astrantias, choisya, spirea. There are lots of perennials out there that would suit.
Don't worry about your garden centre experience, not all of them will be like that, there are some who genuinely care about the plants they sell.
If you get the chance you could visit a garden to see how they plant. Wisley is good as there are 'rooms' and borders of all shapes and sizes.
Looking at the pics of your space, your garden looks very similar in shape to one that Chris Beardshaw is helping to create in Beechgrove Garden (on tomorrow BBC2 Scotland or Sunday BBC2) that also might give you ideas too.