Two quotes, £400 difference - thoughts?

[mrak]

Hi there,

I've had some issues with my power steering (posted in m59 thread) and as part of the solution I've decided to have the aux belt replaced, and get the cam belt (and water pump) done at the same time (it's due). I also need to have the front driver's side ball joint replaced. I've had two quotes. One for £800-850, and another for £440. The garage reviews for the more expensive one are better. The other one does have a few "this guy tried to rip me off" reviews.

My questions, I guess, are: do the quotes seem reasonable, and should I risk the other garage for the savings?

Thanks!

[Gadgetman]

Front driver's side ball joint?
Check the quotes and pick the one who wants to replace the ball joints on both sides.

[mrak]

Front driver's side ball joint?  
Check the quotes and pick the one who wants to replace the ball joints on both sides.

Both quotes are for the one side as that's the side that I was told needed to be replaced. I'm sure I can ask either to do the other as well, but still curious about the difference in quotes and whether the prices reflect the reality of what I should be paying.

[Gadgetman]

Huh?
A pro should have advised you to replace the joint on both sides at the same time to keep the wear even and the handling as balanced as possible.

[mrak]

Huh?    
A pro should have advised you to replace the joint on both sides at the same time to keep the wear even and the handling as balanced as possible.

I guess they're not pros. I certainly am not - that's why I'm going to a garage. Do you have a recommendation for a garage in London?