Vauxhall Astra astra gears jamming in slow traffic

Afternoon all,

I'm new to the forum and a new car owner having bought my Astra at auction on Sunday. I have been having an intermittent problem with it ever since...

I started having trouble after just a mile of driving once I had bought the car. Sitting in slow moving traffic, I noticed that the clutch bite point had dropped right down to the bottom of the foot well and the previously smooth gearbox became very stiff to operate. A few minutes later it became impossible to get the car into gear and I had to fire the hazards on and pull over.
As soon as the ignition was switched off, the gears would operate fine but the car had to be left for a few minutes before the problem disappeared...

I contacted my sister's garage by phone and they reckoned that with the car having done 80.000 miles, the clutch had probably gone and recommended calling a clutch specialist that was likely to charge around £250 to have it replaced.
I did just that and took the car to a garage offering such a service. The mechanic revved the engine, went through the gears, checked the oil levels and instantly recognized that the clutch had gone despite none of the previous jamming symptoms arising. I was quoted £160 for a new clutch, possibly more depending on whether or not the flywheel needed replaced.

Suspicious of how quickly he had come to this conclusion, I decided to get a second opinion and after asking a couple of mates for a recommendation, took the car to a nearby garage with several very positive online reviews.
They took the car for a spin but could find no fault with the gearbox or clutch but discovered that the O/S rear bearings had gone.
On closer inspection on the ramp, the bearings were so badly trashed that the wheel flopped to one side. I had noticed no concerning bearing noises in slow traffic, luckily I hadn't taken it out on the M8 at high speed!
It also turned out that the O/S front caliper was sticking and was heating up considerably.
The initial diagnosis for the clutch issue was therefore that the heat from the sticking caliper was affecting the temperature of the clutch fluid and causing the jamming problem.
£366 lighter after a new hub, caliper and track rod ends had been installed, I sulked along the road for a while with all seeming to be in order.
I then hit slow moving traffic once again and the same problem re-occurred, forcing me to hit the hazards and pull over until the gearbox loosened again. I limped the rest of the way home mostly in second gear and contacted the garage.

The following morning, I took the car back in and the mechanic took it for a second spin. Again, he could find no fault whatsoever but offered to drain some fluid from the clutch in case there was any trapped air caused by a worn master cylinder (?).
After doing so, I went for another spin around town, lasted about 5 miles and then the same problem occurred.

Got back on the blower, told to take it back in again the next morning. Went back with the car today and the owner drove the car, testing all the gears thoroughly with me sitting in the passenger seat. After at least 20 minutes and my face reddening steadily, I came to the conclusion that it must be my driving style that's at fault. It's been a while since I felt like such a nuisance! There was not one hiccup with the car (which in many ways is good news!) and the chap seemed a bit pissed off...

I headed off yet again for a spin round town this afternoon, scrutinizing my every bloody gear change, making sure every one was super smooth.
All went well in fast moving traffic, heck it must have been my driving style after all... until I hit rush hour.
It seems as if this problem only rears it's head in slow moving traffic when heavy clutch usage is necessary... I had to put on the hazards, blocking the left lane of the expressway until the car cooled enough for me to stick it into gear. Even with the engine switched off, it was impossible to engage gear for a good 20 seconds...

I have called the garage again but they can't fit me until next week and frankly I think they can't be bothered with my 'imaginary' problem! I'm now wondering what I should do?
I can't waste the mechanic's time getting him to sit in rush hour traffic but how else can they diagnose what's going on? I'm getting frustrated and would appreciate any suggestions on which avenues I should explore next...

Any help with this would be greatly appreciated.


I should add that I was with a very knowledgeable friend at the time of purchase who tested the car as much as the auction would allow and didn't just buy this monster on a whim... You takes your chances I guess!