VW Golf MK4 GT TDi Heavy Steering Problems

[Time Dependant]

Hi all,
it's been a while since I've posted on here which could be a good thing or a bad thing depending on your views of life ; )
Recentley I've been experiencing some steering issues with my Golf which I'm becoming concerned about which I hope someone can help diagnose where the problem could be coming from.
There are two times when I can really notice issues with the steering:

1). If I put the steering wheel on full lock clockwise or anti clockwise when turning a corner I hear a moaning sound coming from the front wheels, the steering really stiffens up and feels like lead weights have been attached to the wheels.
2). If I'm driving in a straight line then move the steering wheel to anti-clockwise again the steering feels very heavy and unpredicatable as to how much give is distributed in the steering wheel.

Getting up to around 80mph feels really uncomfortable I'm getting alot of play in the steering wheel and it's making me paranoid something could go snap very soon.

The model of Golf is:
GT TDi 130bhp on an 03 plate. All standard build parts I've not made any modifications to the car.

I've had it in the garage and explained the problems they have checked the following and said they could feel the problems but didn't know where it was coming from:

They have checked:
CV joints
brakes
front and rear bushes
front and rear suspension

Would any of this be related to a faulty ECU which could be making the engine run irractically causing problems with steering?

If anyone can even give some pointers as to what I should be telling the garage to look for I would appreciate it as I'm doing an 80 mile round trip each day and I get the feeling something bad could happen soon!!

[Issac Hunt]

Get it to a garage who know what they are doing would be a good start!

Saying they dont know where it is from would not fill me will confidence at all, I'd be voting with my feet and going elsewhere.

Why are they checking the rear suspension?! Get the drive belt, steering rack, PAS pump, fluid levels checked for starters. Also worth a VAG-COM scan to see if/what fault codes are stored.

[Time Dependant]

I laughed when they said it just amde me worry about all the other customers which had gone in to have work done.

I forgot mention fluid levels were checked by myself they all seemed ok

Get it to a garage who know what they are doing would be a good start!

Saying they dont know where it is from would not fill me will confidence at all, I'd be voting with my feet and going elsewhere.

Why are they checking the rear suspension?! Get the drive belt, steering rack, PAS pump, fluid levels checked for starters. Also worth a VAG-COM scan to see if/what fault codes are stored.