I agree that you’re unlikely to get anything decent for £40. the very cheapest racks strap onto the car (causing scratches and dents and lots of scary wobbling) and give you two long poles onto which you just pile up the bikes. you’re left having to strap the bikes on any way you can. they’re really not very good.
You get what you pay for definitely.
We’ve tried a few of the cheaper options and now use a towbar mounted, wheel-support Pendle, which we’ve been using for about 8 years.
We can get into the boot, even with bikes on the rack. We usually remove the rack between rides, but that’s just a matter of unplugging the electrics, pulling a split-pin and lifting the rack. it takes about 10 seconds and we store it on the drive. It doesn’t stick out that far behind the car that parking’s a problem, although it might be an issue of you’ve got a huge long estate, mondeo for example.
The rack’s very stable at high motorway speeds and when having fun on twisty roads. I’ve never had a roof rack, but people who’ve had both say you get much better fuel economy with the bikes behind the car than on top. It’s nice to be able to look in the mirror and see that the bikes are OK rather too.
The brake rotors haven’t bent yet. 🙂