On Pulling Release handle in drivers footwell. No resistence is felt. suspected broken cable. Require a method of releasing bonnet catch or gaining access to cable locations .

Can you see the end of the cable through the front grille? On some vehicles you can use a extra long flat screwdriver to push the release through the front grille.
Some S3 and A3 models have a small access hole between the bonnet and grille. A thin wire hook and a lot of poking around can release the bonnet.
if this doesn't work you might have to destroy the front grille to get access.

You may have a broken/disconnected release cable from the release handle to the lock mechanism. If there is no pressure on the release handle when you activate it a cable would be suspected. If handle feels like there is resistance on it ( cable connected ) try pushing back on the top of the seat while pulling the release handle. The cable could have some stretch and not release the latch properly

this is a lot easier said than done. the easiest way that i know and have done is gain access to the cable closest to the handle, this seems to be the most common place a cable breaks, the next would be at the latch itself. very rarely do the break in the middle. any way, gain access to the cable and cut it. once you have cut it peel off the plastic protective coating. after this is done it you should see the outer steel shell that houses the cable. most of these outer shells are not solid but more of a tight coil configuration. with a good pair of pliers you can "unravel" the outer shell to gain access to the inner cable. hold the outer cable with pliers and using another pair of pliers pull the inner cable and the hood latch should release. this is the easiest way to do it with out chewing your hands up

At the left floor the cable that releases the hood is behind the kick panel. The plastic handle that broke off can be accessed by removing the panel and you will see the last bit of the plastic handle that is threaded on the steel rod. I an emergency you can grab the rod with pliers and pull to release the hood (bonnet). Go to you local dealer and you can order a new handle or go to a wrecking yard and find your car model and just remove and purchase the used handle. You may be able to grab the rod that the handle broke off from with out removing the panel. Good luck.

You don't specify whether its just that you can't find the release catch, or whether the release catch is stuck / broken,

In the UK (Right hand drive car) the release catch is situated in the left (passenger side) footwell, within about a foot of the lower front door hinge. In a Left Hand Drive car, I guess this would be reversed (i.e. right hand side footwell). Pull, and it semi releases the hood. Next, walk to the front of the car, pull the hood up about 1" and insert your fingers about a foot left of center. Sweep to the right, and you'll release the secondary catch and the hood will be open.

However, if its stuck / broken, then ......

You need to work underneath the front of the vehicle - the idea is to get at the catch and release it with a long screwdriver flicking the catch to open the bonnet -or getting a grip of the cable if it is hanging loose ( i.e. broken ) then getting a grip of the cable with mole grips or even pliers - to pull and release the cable / bonnet.

Once the bonnet is open - you can deal with renewing the cable assembly, or greasing it thoroughly.

There is a release cable that is attatched to the red releas handle on the drivers under dash panel. You can grab that cable with needle nose pliers to release the hood to the first detent if the handle or cable is broken. There is a secondary release mechanism(called a hood tongue) which routes through the grille where the rectangular slot is once the hood is popped up with the release handle.you can grab the rest of the broken hood tongue with needle nose pliers and pull it out to completly release the hood from the saftey catch. If it is completely broken you can take a long screw driver and push the saftey catch( i beleive to the right) and the hood should be able to open all the way up. Both the hood tongue and the cable(securing portion at release handle) are common failures and break over the years.if it is at the release handle you are having a problem-get a #2 phillips screw driver and remove the release handle to gain access to the loose cable. I hope I have been helpful

Do you feel any resistance when you pull the lever? If not, your cable is diconnected, probably behind the lever. If you feel resistance, your latch may not be functioning... may have to manually release through front grille.

Most of the time the cable snaps at the release handle. If you remove the handle and get the end of the cable, you can cut off the cable jacket and use needle nose pliers or vise grips to grab the cable and pull to release bonnet.

On mine, a RHD, it is a plastic lever just forward of the door post. It is a crappy piece of plastic about four inches long.Mine has recently broken and will result in a bill for about £60-70 for replacing the lever and the cable (the cable is very tight)
Getting the handle off was a hell of a job until someone spotted that inside the handle, on the lower part as accessed from the outside, is a clip that needs to be pulled out to release the handle. Only then could we reach the cable and that took an enourmopus amount of effirt to release the bonnet.
As the mechanic said, "I didn't expect this sort of rubbish from VW"