Tow bars are simply the best option, if you can afford it.

The models that attach on the back of the rear hatch, in my opinion, are not very good. They can scrath the paint work or the glass, possibly obscure the rear lights and part of the number plates.

Roof mounted are good, if you can manage to lift the bikes onto the roof and clip on. They do not move in strong winds and do not affect the handling of the car. Just remember you may be restricted on entering some car parks with height restrictions.

My first bike carrier was a 'hang off the back' type which I used with a Mondeo estate. The bikes never felt too secure - they tended to swivel round and bang into one another to the extent that I had to put in extra padding; also, the number plate was obscured. A friend had a similar device which she hung from the back of her Corsa. When she asked me to check it for her, I pointed out that the top hooks had pulled and distorted the bodywork, creating two small airscoops on the top of her car!

In the end, as I already had a tow-bar fitted, I went for the expensive option and bought an Atera Strada. I have to say that I am very pleased with it - it's easy to use, the bikes are secure, the whole thing is lockable and the number plates/lights are integral to it. The only real downside is the cost of the tow-bar - when I changed vehicles (after 13 years), I had to have a tow-bar fitted to the new car. Having seen mine in action, a friend has fitted a tow-bar to his car and is using a similar Thule carrier. Another friend has bought a cheaper model of the Thule, which I haven't seen yet, but it employs the same priclipal.

In the end, the decision comes down to how often you need to carry bikes and the need to fit a tow-bar to your current - and subsequent, cars. The carrier itself may appear expensive, but it should last for years.

I don't know about the Pendle design, but many 'strap-on' types are used illegally because they obscure the number plate and lights, the driver not bothering to use a tail-board. Most appear to get away with it but, knowing my luck, the police would stop me.

Having said that, I haven't seen so much of this just lately so, maybe the police (who?) are cracking down on it.