Posted: 17/06/2017 at 11:57
There are only 2 choices for the dandelions really, either dig the roots out or use a glyphosate-based weedkiller and wait 6 weeks to ensure it is translocated into the roots to kill them, so depends on how quickly you want to lay the new lawn. As far as the path goes, it depends on how deep and compacted the sub-base is - a pick axe and garden fork should break it up. If the pebbles and base chippings are small you could just dig them in over the whole area to improve drainage otherwise you would need to skip them.
Personally, I would use weedkiller, wait 6 weeks, use this time to break up the path and then rotovate the whole area before raking level and perhaps adding a thin layer of topsoil before laying turf.