Hi Richard and Linda, Thank you very much for your assistance in identifying the tree. That's definitely it! It's been interesting reading up on it.

That link was also going to be bad. This one should work: https://picasaweb.google.com/bgoodr/PlantIdentificationShrubWithWhiteFlowers?authuser=0amp;authkey=Gv1sRgCJWmu_6bivyozwE&feat=directlink Here is a link that might be useful: Plant Identification: Shrub with White Flowers (second attempt)

I think it's Mirabilis jalapa - common name "Four O'clocks" as they are supposed to open late afternoon. There are various colours from white through pink and red and yellows, and you can get speckles and split colours. Faintly scented. They set rather large single seeds, and they form a large underground tuber like a dahlia. Very hardy, sometimes a bit weedy but easy enough to remove surplus plants once you know what they look like.

It's something like Tephrocactus articulatus var. strobiliformis .