Well that was a fiddly 4 hours work !!, took the panel off & Steve was right regulator had come off the channel at the bottom of the glass, there are 3 little plastic wheels that run up & down horizontally & these can wear out over time & get wobbly, i read a little bit of info on the net regarding the regulator & in order to get the wheels back into the channel you have to undo all the bolts that hold the regulator into the door, then you can manouver the wheels back into place & put the bolts back into the regulator & motor housing, so i did this & if im honest its a very fiddly job, but got there in the end, however..... the window went up a down a couple of time &..... yep it jumped again Grrr!!, so took it all apart , put it back together & re-tried, this time i was watching everything very closely, & noticed the wheel got to the
end of the channel & almost came off before running back in again, now i thought this was normal, tried it again a few times & yep it jumped straight off again, so was resigned to the fact that the wheels were so worn out that any movement on the wheel at the end of the channel was enough to make it jump off the end.
A look on the net & i managed to find these
& this is a video on how to fit them
http://www.youtube.com/watch?v=iMjSWUWu9LQ
from Rennbay.com in the U.S for £26 inc postage, so i ordered a set, but as i needed a working window until these arrived i phoned Ben at Faze1 & he had a spare drivers side door with a regulator inside, so i popped round there, tools in hand & removed it, came back home, fitted the replacement regulator & thought that was going to be the end of the saga.... not so, again the window went up a down a few times & then off it jumped again !!.. patience running thin i looked at the channels themselves wondering if they had become bent making the wheels run at an angle, so i tried to get a pair of molegrips inside the door to bend it back, but there wasnt enough space, so i removed the glass from the door to make the job easier... fortunately for me i did this as i soon discovered the root cause of the problem.... the whole bottom channel had moved along the bottom of the glass by about 1.5 inches from where it should have been, allowing the wheel to run further along the channel than they had intended to & jump off the end !!, another trip to Ben for the glass confirmed how much it had moved by, so i fitted the glass.. & the regulator etc & now it runs perfectly again[

], will wait for the new plastic wheels to arrive before i tackle the job again, but with it being in & out so often & reckon i can do the job in under 15 mins now !!
Sorry for the long post, but im sure this is going to save someone a real headache if this happens to them. Cheers, Jinxy