wanted to ask anyone if they have had this problem or know anyone has.
rockhopper stnd frame ugraded with hope mini's, mavic 317 rims , hope hubs and (i think the crucial bit here) hope titanium quick release skewers.... Coming down blaka moor (peak district) at full speed did the plunge at the bottom and stopped to bullshit with the guys i was riding with. Set off on the track back to Dore pulled really hard on pedals and the wheel shifted out of the rear dropouts and jammed against frame! This had happened before going up hill on a leisure ride wit wife but put it down to the fact that I hadnt checked them after they were put on! I know theres some stuff about this with disc brakes and quick release, any feedback appreciated
(They were done up fairly tightly before some smart ass says that!)

Disk brakes and QR levers don't get along too well. Buy a pair of Shimano steel QR skewers - they have a better closing action and steel grips the dropouts better. They might not be as light or flash as your Hope QR's but going @rse over tit when your wheel drops off isn't very flash either.
Check they're nice and tight before every ride and you might want to give them a quick check during the ride if you're doing a lot of heavy braking. Also try and set your QR lever in the same position every time, you can then do a quick visual check when riding along and if the levers moved round you know it's starting to loosen.

The issue with QRs is resticted to the front only. As the caliper is in front of the axle at the rear, any force is actually pushing the axle up into the dropouts.

strangely it was shimano skewers that i took off, suppose shouldnt be as anal about weight or looking flash! See what ur saying bought directions, front wheel was defo loose yesterday when i cleaned the steed. No way could i do with v brakes now though, disc forever i say. cheers for the feedback

Lost my front wheel out of my forks the other day dumping me on the road after bunny hopping off a kerb badly bruised and winded. Hope hub with hope steel Q/R in Pace fork (no safety lip on drop outs) 1st time in 35 years using Q/R skewers that I have had one loosen off. I will be checking them regularily from now on makes you feel very vunerable on a long high speed descent.

Unlikely that the *rear* wheel could be pulled out of the dropout on braking. The axis of the caliper is generally above/ slightly forward of the rear axle, meaning that the braking forces tend to push the rear axle into the dropouts rather than pull it out. The caliper on the other hand is behind the axle... ;-)
Occasionally the rear wheel will shift in the dropout if you're really caning it and moshing the pedals with the QR not fully snug.

I use steel Salsa skewers.