As the appearance of the garden has a modernist style with the straight lines and concrete furniture how about a Mondrian influence and add a bold strip of blue? It is a pond and with the right shade it could look really relaxed and contemporary. My daughter's suggestion is a chalky lilac!

The blue is awesome (grey is too trendy)! The reason it stands out to you is perhaps because it's the only real colour there. Bring in the blue in a window treatment, a small appliance that sits on the counter, a pretty tray or area rug. Also, it is more appealing often if there are more than 2 colours - so right now you have a white and blue colour scheme - bring in red or orange or fushia - something from the other side of the spectrum (like you did with the yellow flowers but in a more permanent way)!

One piece of coloured glass will give almost the same visual appearance but without the hassle - I do however not have a splash back but I do love to watch many programs relating to renovation. You can also have a piece of art work installed behind plain glass - it depends on your taste.

What colour ? What about some sort of apricot , to go with the pear of cushions ? hahaha . . . . . . . . . . . . Maybe an Apple tablet , strawberry curtains , a banana lounge , but I don't know how to finish it off , something to be the cherry on top ? Oh , I know , cream walls . . . . . . . . .