What's killing my lawn?

[Speed Gardener]

I had a new lawn laid as part of the redesign of my garden. It looked great, was growing great, until a couple of months ago when I noticed brown patches appearing on it. I had a look last week and saw that in the brown patches, there were lots of circular holes in the thatch of the lawn. I presume these are some type of pest, such as chafer grubs or leatherjackets. I don't know as I've never had this problem before.
Anyone got any ideas? Thanks in advance!

[Guest]

How bizarre. Try lifting a piece up with a spade to see if you can see anything lurking. I have loads of chaffers but I have never noticed damage like that before and they are found close to the surface. I am rather intrigued (yes I know, I need to get out more).

[lottie dolly]

How To Kill, Control & Prevent Chinch Bugs in the Lawn - Ortho

try this

[Nicos]

Not sure...but I'd go with some sort of grubs...have you seen birds pecking away at the lawn???

[Jungle Jane]

I think it's birds helping out/feeding on the grubs too,if they're shallow holes,especially after the rain & them coming to the surface. The grubs are the primary problem. There's nematodes you could use to get rid of them,applied in July it says in this link-

https://www.rhs.org.uk/advice/profile?PID=487

I read on a lawn care company website to water the grass in the evening,cover with some plastic cover,remove the cover 6-7am for the birds...
I didn't copy & paste it because it was an advert & we don't want any of that!