On Friday, 5 February 2016 22:53:35 UTC, Dave Hill wrote:

I'm wondering, when you got rid of the the patio and sub base did you
clear it right away at the edges so that you were into soil or did you
just clear the bulk and leave the edges?

I took advantage of the fact that I had both a skip and plenty of enthusiasm and so was fairly liberal with my clearance gettig rid of as much I could tell was 'not good' - this included the sand/cement sub-base obviously but also the more clayey of soil that resembled plasticine.

If you left the edges then you have probably created a semi pond so that
the water is being slow to drain into the surrounding ground.

The brick walls will inevitably be causing an edge effect however the bottom of the garden underneath the decking is actually a recessed bowl. You can hopefully just about make this out in the following image (the turf is level with the top of those flags):

http://www.newtonnet.co.uk/garden/#100_0943.JPG

Furthermore, within that bowl (bottom right) is a rainwater drain manhole cover which, whilst not open, is not watertight and so I would expect it to allow some egress of excess water.

This drainage problem is probably why there was a patio there and not a
lawn.

I was fearing that and hoping that the old(er) couple that lived here before were just a big fan of roses and flower beds!

The "Grubs" you have found wont make it ant better for the grass.

I lifted a square foot of weed fabric I laid down last night and found these (high res images for zooming):

http://www.newtonnet.co.uk/permanent/grubs1.jpg
http://www.newtonnet.co.uk/permanent/grubs2.jpg (probably around 50 of these in a ball)
http://www.newtonnet.co.uk/permanent/grubs3.jpg

Looking at your pictures again it looks as if you have built a brick Dam
on the right hand side with no gaps between the bricks for water to
drain out, and it's this; right hand side; that looks the worst hit.

There are some weep hole in the mortar joints but whether they are working I don't know.

On the bright side the chances are that after this winter we wont have
another prolonged soak like we are having for several years so over
sowing in the spring could well give you a good lawn back.

Finger's crossed but I fear that this type of weather might be the shape of things to come!

Hope this helps a little.

It does; thanks David. Indeed thank you to everyone that has taken the time to chip in.

Mathew