It all depends on the type of weed barrier used and the aspect for the plantings, i would tackle the bindweed first, dig it all out, yes its labour intensive but worth it in the long term, get the soil in good condition incorporate plenty of compost etc and plant out with plants which suit that aspect, some people use bark chips over a membrane, personally i am not keen on this as the bark naturally breaks down and creates a weedbed, the secret is once the border has been dug over then its a case of keeping on top of it and you cannot beat the good old hoe, once a week go over it scuffing any small weeds that appear, the border will always look tidy,if the she wants to use gravel then a good membrane and the correct plantings are a must, and consideration to the aspect is important, ie overhanging trees etc.

Digging out bindweed is easier said than done as the roots go down very deep, and the tiniest bit left in the ground will grow back. If you were to dig down a foot or so you would see a network of horrible thick white roots (nicknamed devil's guts) and every little bit will grow. Another method is to place canes by the bindweed and encourage it to climb them instead of the other plants. Then lie the canes flat, protect surrounding plants and spray with deep root killer. It will probably take several years to start winning the battle. I wouldn't use membrane myself - hoeing is effective. Bindweed will find and grow through any little holes in the membrane where plants are growing, and it will then be very difficult to get it out as you wouldn't be able to dig down for it.

Hi Jennies welcome to GOY,
I agree with Stera. I am digging out bindweed and bishop weed from a bed of perennials where i used membrane. I found it difficult to plant through too. (Later on when planting a shrubbery I used old newspapers laid on the soil after the planting was done and I had fed the shrubs.Then I put a mulch of bark over the paper to stop it blowing away. I used fresh bark from the local sawmill as it cost a fraction of what it would have cost to use bagged rotted bark.) I am finding these roots 2' down. and sinking. I am using the soil to plant potatoes this year and will use his method of deep root eradication. I think if you dig up some of the shrubs which have died you might find they have not been planted properly. They look lovely growing in their pots in the garden centre but they cannot just be plonked in to the garden. Care must be taken to dig a hole big enough to hold at least twice what the original pot had in it and then the roots need to be teased out a little so that they grow out instead of going round and round as they did in the pot. I also mix bone meal in with the soil I am planting in to. I find it helps the roots grow. If some of the shrubs are not quite dead you might be able to give them a better start by digging them up and replanting. Also prune off any dead or straggly bits. Remember new planting requires to be thoroughly watered for at least the first summer. Good luck it sounds as if you have your work cut out.

Agree with Steragram - I'd bet the previous owner used the membrane to try to suppress (temporarily) the bindweed growth. As for the planting mostly being dead, depends what they plants were and when they were planted as to the cause - if they were not all fully hardy, the winter might have finished them, or alternatively, they were new plants and weren't kept watered.
I'd never use membrane where there's bindweed - it's a constant fight against the blasted stuff, but I would attempt to dig out as much as possible when preparing the area for replanting, and then use the treatment described by Steragram. If the soil is light and sandy, it should be easier to remove quite a lot of the bindweed root by pulling gently, drawing it out. If the soil's heavy, well, that's a different matter, no easy answer. Bindweed is a constant companion once it's in the garden I'm afraid.

Thank you to everyone who responded, I had a feeling there wasn't an easy option to bindweed! We'll take up the weed barrier and get digging! Hope to be able to add some photos later on. Thanks again.