Wasn't there last night and have never taxied an A340 but have nearly come off a taxi way in an A321 despite going pretty slowly and being very carefull so bad luck fellas, could have been any one of us, hope your Chief Pilot thinks the same.
Remote de-icing is great where it works well (MUN for instance, and loads of Scandi airports) and a complete nightmare where it doesn't (CDG!). It also needs a good lot of spare tarmac, something which is very lacking at LHR. The sad fact is that the place is so busy that any slight spanner in the works causes chaos and remote de-icing would not make a huge difference to the delays. Just hope you are on a day off when it happens like I was yesterday.