It works
Ok, so I got one, and it does fit.
I've attached three pictures - the rack with no bike, with a bike and the view from inside.
It took some experimentation to find the best position. I've ended up mounting it pretty high - the reason for this is so that the bike is fully clear of the number plate (see "mounted" pic). This means that all four feet of the bike rack are resting on the rear window, which makes me a little nervous but it seems to be pretty solid.
The position of the bike means that the rear lights shine through the spokes. I've not managed to get a properly clear interpretation of the law on obstruction of lights, but objectively, the lights are well and clearly visible through the spokes.
In use, the rack is solid and firm once you've tightened up the straps. There are two hooks at the top and two at the bottom. Following advice from elsewhere on the internet I superglued a piece of innertube into each metal hook so that it would not damage the paintwork. To keep the lower straps clear of the number plate I've had to put them at an angle. To prevent them sliding back towards vertical (and hence becoming loose) I've superglued a nut to the inside of the lower lip of the boot on each side so that the hook can't slide past it.
The bike is held on by two clips on the crossbar and a strap around the seat post. I added a couple of bungees to hold the lower part of the bike steady and stop the wheels from rotating (and prevent the front one from turning side to side and hitting the car). The left pedal rests on the car, so I put an old glove on the pedal to protect the bodywork.
With this arrangement the bike is solidly held, and does not move around. I travelled a 40 mile round-trip commute, with the maximum speed being almost 60, and some roads had considerable crosswind. The bike held firm throughout.
Mounting the rack on the car takes seconds. After the initial adjustments to get everything right, I remove the rack by loosening the bottom straps only. When I put it back on, I just need to hang it by the top straps, and then hook on and tighten up the bottom ones. I've only done two trips, and yet I can get the bike + rack installed or removed in under five minutes.
Conclusion: Ideal for me, I use it for commuting so it needs to be quick & easy to use. When I reach the park & ride I can stash the rack quickly and easily in the boot. It holds the bike firmly but I haven't tested it at motorway speeds. The Saris documentation itself says not to go over 60. So maybe not ideal if you want to take your bike long distances. You will need more padding material and securing straps/bungees than what is provided in the box.
