Weed proof membrane and relaying lawn/flower bed over top.

If you lay tarmac on your garden before adding topsoil, Carl, bindweed will still come through! Just laying a membrane is not the answere. I would suggest using a suitable weedkiller on the the garden and then leaving it for a period of time as advised on the weedkiller container. Then lay your membrane and soil. That is the easy way of doing things but proper digging and weeding would be better.

Not a good idea at all - if you lay weed membrane and then try planting over the top, it'll be impossible to dig out anything you don't want when that grows - and if there's bindweed, it will grow, and in the meantime, spread its roots even further beneath the membrane till it finds escape routes.

Bindweed is a pain and a friend for life, usually - if your soil is light, then now is the time to dig over and extract as much root as you can, before you import any topsoil. If you have heavy soil, you can still do the same, but root extraction won't be quite as successful as with sandy light soil.

Once you've planted and turfed, then I'm afraid its the very boring treatment of inserting a bamboo cane where you see bindweed growth appearing, allowing it to grow up the canes, then spraying with glyphosate, without getting the spray on any surrounding plants or turf.

I don't have this problem in our garden but I really like that last idea, Bamboo!

It's not attractive though, Bulba - in a friend's garden last year, it looked like he was growing a forest of sticks....

I've done it and it did work - eventually...

Whatever you do, do it without membrane.