Having read good things about this (and having seen some pictures of the blue one attached to some of the new Mk 1s from Farish) I decided to get one on a whim as it doesn't fit my modelling interests - they were mostly based in Scotland I believe.
My example arrived last Friday (21st) and ran beautifully from the box. No dramas at all. The only complaint I had (and this is almost universal with my new era diesels) is the red is on all the time and cannot be switched off - OK when running light engine but not too flash when hauling a train. The other minor grumble I have is the blue seems to be a bit too green when compared with other Blue Era models I have (and not just the Farish ones - seems Dapol have changed the paint spec).
I went to put a TCS EUN651 chip in it and that was when the trouble started. The instructions don't warn you the lights are attached to the chassis. I found out that they are plugged in from a post here on the N Gauge Forum. Initial efforts to put the chip in proved to be far from easy. To start with the body wouldn't sit down correctly so after a few attempts I removed the chip and put the blanking plug back - the blanking plug is noticeably shorter than the chip I chose so I wondered if the chip wasn't the best choice. No dramas really I figured I would email Dapol and ask.
As it happened, the wires leading from the plug leading to the LED cluster managed to work loose. The infamous Dapol dry solder joints seem to have finally struck me. Mind you, I don't have a lot of Dapol locos as I have been made gun shy of them by the horror stories of the Mk 1 versions - although the diesels tend not to have these in the same abundance as the steam locos. Now sending it back is usually the cry in case like this - and fair enough too. The loco had merely been run for an hour and now one set of LEDs wouldn't light up merely by the owner attempting to DCC the loco. No tools near it.
Since I was emailing Dapol about the chip I added the information about the light. Joel @ Dapol replied quite quickly asking, not unreasonably I thought, for photos. So I sent them off. Nothing heard from them since so a bit disappointed considering there was a few hours left in the business day over there when I emailed the second time - POETS perhaps?
Fortunately I have been able to fix the LED cluster (seems the soldering of 2mm kits has paid off in other ways!) and by removing some padding and replacing it will some tape (since I assume the padding is part of the insulation protection for the plug) I have fitted the chip of choice and the loco is now happily trundling around DCC and ready to go. Still have the red LED issue to sort.
I have discovered one other niggle - the coupling pocket. It would be handy if Dapol included a bogie surround which was minus the pocket - or even a spare which the owner could cut the pocket off. The pipes and bits which are included in the bag can only be fitted as far as I can tell with the coupling pocket removed. Now this would render the locomotive as a one direction loco. Not a problem for a DVT or a steam engine (such as the forthcoming A3 or A4) but on a 26 it is a bit of a pain. More because if you change your mind and remove the pipes to sell the loco in the future you can't replace the coupling. So I am not sure - I haven't worked out a train for this loco yet but it may end up hauling some Mk 1 coaches with Sc numbers whereupon I may remove the coupling and put the pipes in. In the meantime, a short shank coupling is going in and we will see what happens.