well I was driving down a street today that resembled main st on the simpsons (monorail episode) and after the 40th pothole something in my suspension broke. Can't work out what it is so I thought I would throw up the symptoms and see if anyone knows.

when i go over speed bumps, the front left wheel has a violent thud like it drops straight down, yet when I press on the bonet above the wheel it's still quite firm so I don't think it's shock absorber. Also when around a corner at speed the wheel shudders roughly like it's not gripping the road, which it never did before. Also when driving along any surface changes like dips, cracks in the rd, etc there is a rough thud.

Any ideas?

either the shock is shot or your bump stops or bushes have worn out
should go and get them check out

Sounds like the shock valving as given up the ghost, or the the seal has busted. Worse case is that you have twisted the K frame enough to misalign everything.

Have you modded suspension, if so what do you have

Check your lower ball joint to begin with, these do come loose in the lower control arm

Also check your bearing plate (strut top)

When you bounce the car on the front left, is it now bouncy and not firm in both diections? If not, then your damper sounds like it may be ok

i think you should first check the ball joints and tie rod ends as Mal said, no use replacing shocks when a worn or damaged ball joint could be the problem. id jack the front wheel off the ground and try to move it holding top and bottom and side to side.