The car looks great, really notice the difference the black badge makes when walking to mine this morning.
Sorry I am a little late to the party re the remap/tuning box side of things!
You are quite local in the area, I would suggest going to Charlie @ Surrey Rolling Road if you do another power run. SRR is known to be quite a reserved but very consistent dyno, in most of the Uk its the benchmark dyno. Its a totally independent rolling road (ie not a garage) that gets used by all sorts of tuners for different manufactures. I have my tuner live map my Monaro from Aus there quite alot.
Although its nice to work in fwhp, I always tend to work in WHP, its far more accurate as you are not guessing at the transmission losses etc.
The dip on the graph is interesting, were you able to track the AFR during the run?
It looks like something is going wrong at 5.5/6/6.5k
On my Octavia I started off with a DTUK box, to be honest I was massively disappointed. I too work by how fast my bum moves on the seat rather then pub numbers on a piece of paper. However the DTUK box felt quicker to stock but compared to a proper map it was obvious it was under performing. I found it very hit and miss, between 1-3rd gear you would sometimes feel the car pull quicker, but 4th the gear would really get going. I wonder if thats the same in yours.
Once I took it off and had the car mapped it was hugely noticeable just how slow the car was before. The car (originally 220hp) would now after the map dust my sisters Golf R.
I find the DTUK response a bit shit too, I know its not simply about the numbers but on the other hand if I were paying for a claimed power output I would expect to get it or atleast close to it taking into account variables
again sorry I know this had been discussed ALOT