I've got to be honest,I don't think you'll get a bike in through the small boot opening.
, the boot opening of the coupe megane is the same as the saloon version. its not a 3 door hatch.
The owner of the dog i look after reguarly has pretty much the same car as me, but my hatchback boot has much better access to the boot than her coupe, (opens atleast 2x as much) if that makes sense.
also, tow things to look out for is a knocking from under the dash board when the car is first started, or if air re-circulation is selected. its the motorised flap, where a small bit of plastic that stops the motor turning breaks off.
and if you decide to get a hatchback, there is a common fault with the back driverside door not unlocking, there is a sticky thread on here somwhere about it.
my megane had both of these problems, i fixed the rear door by getting a 2nd hand locking mechanism from the scrappers, but the air box problem has remained, as it would involve removing parts of the air con system, but it will still work, just clunks a few times when you start the car.