Quickest was to clear my lawn for re turfing?

Hi Vic
The way I would start is to take a spade and cut into the grass in a line the full length of it around 3 inches deep , then cut across each long length creating square turfs approx 12inches square , then take a garden fork and lift each turf , turn them upside down and pack in a remote part of the garden they will break down into lovely soil eventually or remove to dump. Now either bring in some top soil if required (2 inches) or rake and level soil, walk area remove stones and trample level, lightly rake ,sprinkle growmore, lay turf.

cant you turn the turfs over and turf over them .i mite be wrong

Agree with Maccrimmon - unless there's more grass than anything else already, in which case I'd remove the weeds, rake up the bare areas, level then sow grass seed. You won't be able to use it properly this year and you'd have to cut the seeded areas with nothing but a hover mower or a pair of shears for the first three cuts, but if the percentage of lawn you have left currently is greater than the area of mud and weeds, that's what I'd do.

Any perennail weeds like dock, dandelion will need CompletelY removing as any bits of root chopped off and left deep in soil will come back through your new lawn.

And keep it watered even if it rains as you need the water to penetrate down deep. If we have a hot spell, it may need weeks or even months of drowning to allow roots down into soil or else a sprinkling every now and then will do it no good and it will go brown and possibly die.
Try lifting a corner every now and then to see if its rooted but still water if hot. YOu will see that its happy when it grows really fast and long. Leave it for about 23- weeks after its rooted and then mow it on a high setting the first few times then lower it a bit. This will stress the new lawn less and also help it establish.