DPC Height and Drainage Problem

[inbetween]

I moved into my new house in February and we are having an issue with drainage in the front lawn by the front door where there is a constant mud patch regardless of the weather. I've attached a photo from the weekend, it never drains but it never really gets any worse either.

I did press a fork down into it and there is something quite solid about 10-15cm underneath but I have no idea what it is but it feels like concrete. I didn't want to touch it in case it's something to do with piping as the gas/electric meter boxes are next to the downpipe that is visible. Could this be a leak of the downpipe or is the large solid thing likely to cause it? I've asked the builder to investigate.

A second thing I've noticed from the same picture is the weep hole vents at the front look very low and virtually at ground level. Should they really be this low and wouldn't this affect the DPC which I think sits below the weep vents? The ground level is at least 2 bricks lower around the back which does sound about right.

Thanks

[Ben823]

I'm no surveyor but I do know that the DPC should be two bricks above ground level.
The builders should either lower the ground level by digging out or install some sort of French drain.

[New Home Expert]

As said DPC should be 150mm ABOVE finished ground level.  If the house in timber frame this is even more vital.
This is why the weep vents are level with the ground!

It does seem likely that there is a slab of concrete under the turf, but this could be protecting shallow drainage or services.
Leave well alone and get the builder to investigate.