I have a Cube bike, and want to replace the current bar grips for a pair with integrated bar ends. Whilst I can see how the grips come off after undoing the small Allen bolt, what I rather embarrassingly cannot see is how to remove the bar end plugs! The grips won't slide over the top of them, and I have tried every way I can think of to prise them off without success. They do not appear to have any external fixing, so I can only assume that there is some internal means of securing them. I don't want to destroy them or damage the ends of the bars. What's the secret, folks?