Oh dear I like Nat King Cole too , but the jazz piano playing Nat as opposed to the crooner Nat.
We have a dry Mediterranean garden too. I raised the levels by about a foot and filled the area with soil and about 6 inches of gravel to aid drainage. I've planted buddleia as a screen against wind and then yuccas, agaves, olive trees , lavender and a few other things to give some summer colour .
I only finished the tropical garden a week or so ago and if you go back 10 pages you should see some photos which Fred very kindly posted . There are tracyhocarpus fotunei ( palm tree) X2 , agapanthus, cordylines, fatsia japonica ( castor oil 2 spiders web and 1 normal ) 7 banana plants ( 5 muso basjo and 2 muso grand Nairn) , a schefflera , a tetrapanix , various grasses , persecaria , ferns , dahlias, acanthus a water feature with umbrella plants and bruchmasia fuschia and a Paulawina.
Fingers crossed that it all grows. It's in a south facing sheltered spot so it has a decent chance if I add some winter protection.