What a treat this garden is. Thanks for sharing it.
I note it's in Zone 8 but know that many of the plants there can survive in colder climates here in the US. I've grown astrantia major (an underappreciated plant, I think), climbing hydrangea petiolaris (when it gets going, get out of its way!) and alliums, among others, in Zones 6 and 7. I hope I can figure out how to save the photos you shared as inspiration during the depths of the next winter. Despite its size and variety, there is a symmetry to this garden that one could only hope to achieve. I picture an artist at work.
It's nice for me to be able to garden in zone 8 again after my 10 years in Maine! I grew astrantia there quite successfully. Bide A Wee does grow some plants that test our zone limit and sadly our very harsh winter has damaged some of them quite severely.
I have more albums of the gardens if you are interested in seeing more.