Loosing coolant + white smoke, EGR cooler leaking?

Recently the low coolant light flashed up on my dash which I didn't think much of at the time, just topped it up. Then roughly a week later the light came back on again and sure enough the coolant level was at the bottom of the reservoir.

I've not noticed any external leaks, but one thing I have noticed when looking out the rear window is an increasing amount of white smoke! The strange thing is its intermittent, one morning I'll not notice anything, the next the car feels a tad sluggish and the white smoke is obvious going at anything under 30mph.

The leak doesn't seem too severe as the reservoir level goes from in-between the maximum and minimum marks to the light on the dash coming on after roughly a week (200-250 miles ish). The coolant is nice and clear and going by the dipstick there doesn't seem to be any in the oil.

After a bit of research it seems that the EGR coolers are somewhat prone to leaking, has anyone else had a problem with the cooler or had similar symptoms? I contemplated using some K-Seal but I'd rather not as I'm worried about it clogging up things it shouldn't!

The engine's a 2.0 TDI 140 BKD. Any help would be much appreciated!

It is an 05 plate, I was hoping that as the oil and coolant don't appear to be mixing it the head might be alright. How can the head all of a sudden go bad? I would have thought if it was an issue with the head it would have presented itself a long time ago!

Not sure about the code on the head will need to look into that, cars got 103k on the clock at the moment. I'll order some K-seal then, with a bit of luck as the leak nothing major it will sort it out!