Hi Martin,

Thank you for the comprehensive reply. I have responded inline:

On Friday, 5 February 2016 17:57:39 UTC, Martin Brown wrote:

What treatments if any have you applied to it?

The only treatment I've ever applied has been a granulated spring/summer 'lawn feed' in June and August last year. I should admit, however, that in August I didn't water it in as we were expecting rain... which didn't occur. A few days later I noticed quite a few *very* yellow patches (tennis racket size max) and the affected areas completely died off. I reseeded these areas with Rolawn Medallion seed (i.e. same type as the turf) and all was restored.

Waterlogging is a distinct possibility this wet year or over feeding or
perhaps inappropriate dosage of weedkiller. Where abouts are you?

Wiltshire (South West). It has been very wet however nothing I would describe as flooding. I do feel that the garden drains well - at least on the surface (no puddles or anything like that) but perhaps underneath (on the clay pan ~8" below) things are different?

It takes a lot to kill grass. The lush bits look a bit too lush to me
which is why I wonder about over feeding with nitrogen.

As above, I could be guilty as charged - at least regarding leaving it on the surface but the dosage levels were right. I don't recall whether those small lush bits coincide with my reseeded bits or not. They do however represent the sort of size of damage I caused though.

Worms don't usually retaliate like that. Although worms coming to the
surface tends to suggest they were trying to avoid drowning in water
sodden soil so they might be a symptom rather than a cause.

I did think that earthworms would be eating rotting matter and not the roots. It is worrying to hear about the reason for surfacing though - perhaps this is indicative of poor drainage underneath then?

Use a fencing spade to take a narrow spade deep chunk out of the worst
affected bit and see if it fills with water quickly or overnight.

Will do. I've just been out to dig a small hole (not big enough for your test though) and did find 2-3 grubs. Will catch and photo some tomorrow for identification.

If it is that the punching a few drainage holes through the clay pan
underneath will help a lot even though it is hard work.

I don't mind that. I am finding it hard work seeing how bad the lawn is looking! ;-)

How much wear does the lawn get?

Very little - only the wife and I (and two cats). As you can probably surmise from the layout, it lends to only a couple of thoroughfares and we all (cats particularly!) tend to stick to them yet the problem is pretty much all over.

It might grow back of its own accord
when the weather improves - worth waiting before doing anything drastic.

Will do.

Walking on soggy lawn will potentially make the grass die by suffocating
the roots.

We are very much fair-weather outdoor types so we can rule that one out!

Don't fret about it too much yet. Wait for spring to see if it comes
back from the remaining roots before you do anything irreversible. Grass
is quite good at recolonising ground when conditions are right.

Thanks. It is reassuring to hear that all might not be lost.

Wait until spring and then give the bare bits a good rake and mix in
some sharp sand and peat followed by a grass seed with similar
characteristics to your turf or maybe a bit harder wearing.

Will do. I've got the majority left of Rolawn seed box and am assuming it lasts? (It it kept in a dry understairs cupboard).

I'm a bit surprised by how bad it went so quickly. Given that it
survived for the first year so well. What else might have happened in
the Autumn that provoked such a serious level of die back?

Nothing that I can think of (other than me not watering in the lawn feed).

One other thing is that we used to have a cat that would regularly eat daddy long legs.. Sadly she passed away and the remaining one is too lazy to have taken over so the Aug/Sep 2015 season went unhunted...

Do you have any intermediate pictures of its decline?

Unfortunately not. Whilst it was photographed regularly during the build (http://www.newtonnet.co.uk/garden/) I've been too ashamed to capture anything on film since its demise started...

It almost looks like it has been overgrazed by rabbits or something. The
part near the step could well be caused by compaction.

No rabbits! ;-) The bit around the step also sees very little use. It is however in shade during the winter months - indeed the whole garden arguably is.

Thanks again for your time and input.

Mathew