Gear change problem and LG getting me down...

Hi folks, new here and looking for a bit of friendly input at the mo. So my 06 Octavia 4x4 (160k) started getting troublesome when getting out of reverse. After a while 1st then second and then finally third got difficult. Non of these were consistent but pretty regular. When I brought the car about 18 months ago it came with a good service history which didn't show a clutch change so I asked the local garage to look at it and change it. I opted for a new clutch and DMF (rightly or wrongly) which when they changed over they said that the DMF was pretty shot and the clutch although not terrible wasn't in great shape. 

I drive out of the garage and all is fine for about twenty miles. then it starts creeping in first... clutch down, brake off... rolling forward on the flat. I take it back and they say that air has probably gotten in and that they need to change the master cylinder which they do at my expense. Problem not really solved but a little better....

Two weeks later and getting in and out of reverse is still really hard sometimes and it feels like every time I put the clutch down it engages at a different point. sometimes its fine, sometimes it snaps in, sometimes getting into first or reverse is really hard. 

The final bit that makes me think it isn't the gear box (apart from the creeping which its still doing sometimes) is that if its stuck in reverse, turning the ignition of and stopping the engine allows me to go to neutral with no bother....

Argh... so I've told the LG that I'm not very happy and want it sorting but it'd be good to have a little bit of ammo to go in there with... If anyone can put in their 2p it'd be really appreciated.