Query about weed suppression membrane
I'm new to this forum and a complete gardening novice so please bear with me.
I am planning to use a turf cutter on various parts of my front and rear garden. In the rear garden I want to create flower beds and for the front garden to remove all the grass to replace it with shingle and put plants onto that.
I was planning to remove the turf, get rid of all the weeds and put a weed suppression membrane down before covering with shingle. I've dug around to see what the state of the ground is like and found that there's already a membrane underneath. Firstly, it clearly isn't working as there are weeds everywhere, secondly it's much deeper than I expected and deeper than the turf cutter was going to go! What should I do with this? Can I leave it and end up in a situation where I have the old membrane, a few inches of soil, and then the new membrane? Could this cause problems with a waterlogged garden? Should I take out the old membrane first?
Many advice is much appreciated