Is there way of opening my bonnet if the pull cable has snapped on my land rover

depends on where it snapped.
If it is accessible under the dash, clamp some vice-grips on it and pull.
If it is broken somewhere under the bonnet it gets a lot trickier as you'll need to find a way to trip the latch. Reply as a comment if we need to explore that.

has the cable snapped if it has its going to be a pig to do if possible and there is access you will have to get under the car and try to get at the bonnet cable pull it by wraping the cable around some pliers or the cable could of just come off the back of the bonnet release lever you will have to do a bit detecting to see where its snapped hopefully it will open if not only other way is to take out the front grill and use a screw driver to pop it open but you will destroy the grill getting at it

do you know were the cable has snapped front or cab ?
cab you need to use a pair of plyers, front snapped.bit more tricky. and its going to cost you a bit more to just get to the cable and you will need to replace parts on the front.

Open bonnet. On top of engine towards the front, is a head cover. Remove that. Remove with caution the HT cables. Get a long socket wrench for plugs and remove each one. Careful with grit that might fall into the piston sleeve. Replace sparks and button all up reverse of the removal.

You have to cut back the outer covering of the cable and pull the inner cable with a pair of neddle nose pliers

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.

Try to put a screwdriver from the front plastic grille, up to the lock mechanism and move it to open the mechanism. If the bonnet has opened slightly , then you need assistance. One person to try to lift the bonnet and another to push the bonnet from side to side.. Unfortunately its not possible to remove the front grille to gain access to the lock without braking the plastic grille, as there are screws holding it to the top valance.

there is a way , if you get under the front of your car . lie on the floor and try to reach the the end of the snapped cable this some plyers and pull it it will unlock it

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.