Yes, I flushed the oil. Wynn's is I believe lots of detergents. It's aimed at shifting varnish and sludge. My car has only every had good oil and changed often.. Except this last time, should be sludge free but every engine will build vanish I guess. Mine has also always run at higher oil temps than most (Based on me asking on an owner's forum). Owner's manual says don't push on until oil at 80C so I take that as bottom end of operating range, the oil is good to 130C but VW put the engine into limp mode to protect itself at 120C. From New mine used to settle at 101-103C. Over the years this had climbed, usually stepping up after an oil change oddly, and it pre flush settled at 108-110C. I wasn't sure the cause and actually thought it more likely that the sensor was drifting out than an oil problem. I tried the flush just because..... You know, you get an idea to try, can't hurt, a can is £6 and few in this case so what the heck. Well now the oil temp is settling at 98-104.C. So back to where it was and it goes up and down much much quicker dependingding on if I'm coasting or climbing a hill or.. I wonder if the oil cooler inlet valve was getting sticky and is now free again? No idea really. Any how, use is easy, get oil hot and ready to drain, switch off and add the Wynn's, idle or fast idle for 20 mins, drain.
Oh and I've heard little using diesel as a flush, that won't shift any non gas soluble varnishes but probably shifts some sludge.
It's definitely done something although I'll never know what or if it was a help, but I've bought 2 cans and will do my wife's car and my own again next oil changes. After that we will see but I'll probably not do it more than every other oil change, at most. Wynn's suggest using every change, but then they would.