somthing is wrong then for me to be losing 100 mile a tank! thats shocking :-(
I used to get better consumption from my tuned
Cupra TDI, so I'd agree, somethings not right.
What code did it give you? A failing MAF would normally act as a restrictor because it'll generally see less air mass than there is, so the ecu will
lower fueling to match the Air mass it thinks is passing the MAF, therefore there would be a reduction in power and efficiency and generally consumption will increase. If it were mine, I'd consider replacing both the MAF (bosch) and coolant temperature sensor for piece of mind, but thats just my opinion.
Regarding the flashing temp light, as you said you've got the 6 dial dash, so this may be another issue all together, and possibly the start of the common tdi sport dash issue.