Alright, alright! No sniggering at the back!
So I've wiggled a great deal to no avail and phoned up the garage who put them in who replied promptly that a) they won't come out and b) they'd be all wrong for my Renthals. Bah, tossers!
So I found some geezers on the net who sell just the Acerbis bar end inner expander bits which almost as soon as I'd ordered them I thought was a complete fsck-up because I'd not thought about the inside diameter of the bars
nor bits of rubber. In fact I'd not really thought about it much at all, I was just impressed that I'd found someone who flogged the bits for �7 a shot.
As it turns out, they're quite unlike the Yamaha fitted ones in the above shot as you can see
.
The main splayable/knurled bit doesn't have a screw thread -- only the tapered bit does which you will be pulling back out of the bar when you tighten, thus splaying the thingy. What's more the knurled bit fits exactly inside the Renthals. In fact, with the taper sqidged on the end it wouldn't go in at all. That's what I call a tight squeeze. Not too much call for a rubber sleeve. It's a completely different diameter thread screw too.
So, for �14 it's looking good.
Cheers,
Ian