Low oil pressure when hot idle

Having low oil pressure when hot at idle, showing just above 1 bar and flashy light, no buzzer

Changed oil pressure switch 
Tried 10w40 sytna 
New filter
Oil pump changed
Gasket check

Been advised as it's done 140k to use 10w50

Thoughts?

Just above 1 bar when hot actually sounds about right.
I know it is on mine when up to temp

Just don't understand why I'm getting oil light come on, it's driving me insane 

flashy light at Idle can be :
Oil pressure issues check with a mechanical gauge.
The low pressure switch is at the back end of the DPWS, and can be issues with knock off senders, and cheap filters.

What filter are you using?

I personally use 20W50 oil and have for years with no blinky light from hades.  Your 10w40 synth may be getting too thin at higher engine temps for the sensor.

Bosch, Fram, and generic store branded filters are know to cause issues.  Stay with Mann, Mahl, Genuine VW, mobile1, stp, pureolator gold or wix as they are known not to cause iffy flicker at idle.

The normal is 1.5 bar at 2000 rpm @80 degrees.

how would you define a cheap oil filter
is it in the construction or just how it
looks in the construction what is the
best metal or silicon  based filtration
systems in your views i have my own

Waiting on genuine filter, see if that and oil
Change helps it, it's just one of many faults at mo.

Mates had it for couple weeks to fix hot start issue, said changing fuel relay seems to have helped it out and hasn't played up since, proof will be in testing it now 🙄

nicci21paul said

how would you define a cheap oil filter
is it in the construction or just how it
looks in the construction what is the
best metal or silicon  based filtration
systems in your views i have my own

Fram, and Bosch most Store branded filters do not have the back flow drain back preventer.  Even tho they don't have this on a VW engine of this type as it is mounted differently this little feature keeps the idle stable at low RPM.  Bosch used to have a good rep about 10 years ago, but they changed their manufacturing of them and eliminated this feature, so they too have been getting flaky issues when warm.  

All the brands I have mentioned I have used over the years and never had an issue as well as WIX and NapaGold (made by WIX).  of them that I mentioned as Bosch, Fram, and Generic have caused me grief….

It isn't what they are made of per say, but how they are made.