So I have the same problem that many people have - The key turns but the bonnet lock does not release the catch. I have read the helpful guides on how to go about it but I just have a quick clarification to ask.

My catch sometimes releases. I am not sure when I can get it looked at or look at it myself but wonder if I can do something now to help make the eventual solution easier. If I get the bonnet open on one of my attempts I can remove the front grill. After I close the bonnet I would be able to easily get in from the front to access the cable from the key to the mechanism at a later stage.

Will this be helpful? If I can access the cable from the key lock can I manually turn it with pliers to release the catch?

Turning the outer cable jacket is what separates the anti-tamper mechanism. It will make it easier for you to open the bonnet though (maybe by removing the bonnet lock itself).

Sorry I don't understand. When you say it will separate the anti-tamper mechanism is that what has to happen? I mean is separating the mechanism how it opens or is making it connect together how it opens? When I turn the key am I actually normally separating the mechanism to unlock the bonnet?

The anti tamper mechanism is what causes some of the inoperable bonnet lock issues - the key turns an internal cable with a cross head socket/plug. If you pull / twist on the whole outer cable assembly the two parts separate and make it inoperable