Removing pane in double glazed door

We have recently moved house and need to install a cat flap. The best available position for the cat flap is in the conservatory. There is a pvc door there with toughened double glazing. From reading posts here, it appears that it is not possible to cut toughened glass. The door is split into two panels - a large panel on top and a smaller one below.

What I am thinking of doing is removing the bottom glass panel (it is small - 1 foot high and 2 feet wide) from the door and replacing it with either a solid pvc or wooden panel and then cut this panel and install the cat flap there.

I am wondering how easy this will be. The pvc door is sealed at the moment and I am wondering will it possible to do what I am hoping.

Anyone done anything like this. Or any other suggestions.

Go to the supplier or manufacturer of the door, they should be able to get either pvc panel made up for you with your cat flap in it, or they could have a new toughened double glazed unit made again with your cat flap in it. Its a regular thing thats asked.