I don't live near you (I'm Derbyshire) but I have the SD1 and the Tyros 2. I know what you mean with the buttons on the Yamaha but personally I don't find it any trouble. Some buttons on the SD1 are also situated close to one another. It's a case of getting used to it. Have you thought of getting a USB light for the Tyros 2 and plugging it in? They work as a mate of mine uses one. He can easily see his music and all buttons when the stage lights are dimmed. He had a few wrong button presses until he got used to all the locations of them.
Both the Tyros 2 and SD1 have fantastic sounds, styles and features but the way they operate is totally different and I find the Yamaha is far easier to set up and navigate out of the 2. The SD1 seems to offer a little more punch in the bass end, but I prefer the styles on the Tyros 2.
My SD1 is actually for sale and I'm going to put it into the Keyboard Cavalcade mag asap.
I've also got a G1000 so having 3 arranger keyboards has become far too much for me.