Lights not come back after running it for a good 30 mins today and driving it round the estate for 5 minutes, brake pedal is awful though feels like I have almost no stopping power and pedal to the floor every time. I've coded out the brake pad sensor just incase that is playing up and causing issue as I noticed the wires were exposed the plastic covering had weathered quite badly.
Checking the brake after a quick drive on the estate showed wildly different looking discs, they were covered in rust before as its been sat a while and here is the passenger rear, nice and clean:
And here is the drivers side (the one I sanded the pads pegs down on):
Either passenger side is dragging and the driver side isn't or I've proper messed up the pads on the drivers side which is contributing to an awful feel as its barely touching or maybe a bit of both.
Probably the level sensor gone funny - I would bridge the terminals.
When you were bleeding did the fluid drop low in the reservoir at any time?
On my Mk4, after bleeding peddle felt good engine off, engine on it turned into a sponge, it was air in the master cylinder from not keeping it topped up.
Easy fix on the Mk4 as it has bleeders there, but Mk5 you would need to crack open the line.
If you have VCDS you can get the ABS pump to bleed the system, very good for ejecting trapped air.
It would drop lower in the reservoir but not below the level sensor. We'll I've got OBD-ELEVEN, think you can do the abs pump via this and a schwaben brake bleeder is in the post so hopefully that's the end of mushy pedal and alarming STOP messages!