Concrete under slabs right in front of Victorian terrace - ok to remove?

[Katawampus]

Hello. Total amateur looking for a little advice if you will...
We want to plant a couple of climbers either side of our front door. We have a Victorian terraced house with a cellar. Took a slab up next to the bay window to find big piece of concrete beneath it, I'm not sure how deep it is but wondered if there's a chance it could be intrinsic to the structure of the house? The cellar is directly below the front room and I'm worried about causing any damage.
Please be gentle - I'm aware how silly I sound!

 

[vinn]

You are not being silly but I might be if I gave you advice on the basis of your post - why not post photos of the "hole" and the doorway?

How deep are the roots of the proposed climbers?