Here is another picture

This one is of what I pulled up.

Is this Bermuda? Does that area get shadded by that big tree?

I am having problems with brown patches on my lawn due to my dog weeing. I followed a forum on the subject and was led to this site as the owner of the post recommending a lawn spray she said she was importing into the UK from her sister site in Arizona. The product is Naturvet GrassSaver Yellow to Green Lawn Spray (32 oz). I've found it for sale in the USA but the postage is 3 times the price of the product! I've not found it in the UK The spray instantly turns the brown grass to green and is non toxic etc. Does anyone know where I can buy this in the UK? It sounds exactly what I need until I can cure the problem and it may help other folk who have brown patches until they too can cure their problem.

mareec, you have a drainage issue leading to the fungal disease. I would treat it with ordinary corn meal from a feed store. Apply at 20 pounds per 1,000 square feet. That will fix the grass, but you still need to fix the drainage so it doesn't pool up there.

bobandchrissie, I would suggest you start a new thread about dog spots on the yard. I've never heard of that product but the solution is much easier than you're making it.

The grass is a combination of bermuda and St. augustine in places. I had a feeling it was because of poor draining conditions, and just needed to confirm it. Thank you for the help, I am definitely trying the cornmeal route. We don't have a problem with animals in the front yard, unless a stray wanders through, which isn't that common in our neighborhood.
Thanks All! :)