These GU10's are a disaster but.......
To remove them use a Mr Muscle Oven Cleaner cap which is orange (at least mine is) off the 300ml can of cleaner.
It's just a little bit larger than the GU10 and its flexible.
Try it with a removed bulb and you'll be able to grip the bulb by squeezing the cap once it's over the bulb.
With the bulb in its holder, and after you've screamed at it a couple of times, push the orange cap over the bulb and squeeze - not too hard. Turn the cap anti-clockwise while squeezing and the bulb will come out.
To put in a new one, although still not easy, look into the bulb holder and you'll see two strange semi-circular slots. At each end is a slightly larger bulge and remember the orientation of these bulges. Holding the bulb with the two 'tits' aligned with the bulges push the bulb into the holder until these locate. Now, while holding the bulb, place the Mr Muscle cap over the bulb, squeeze and turn clockwise. The bulb should lock.
Don't squeeze our push too hard. If you damage the bulb you will have to remove the complete assembly which is messy.