I'll bet a tenner you won't get anyone in any department anywhere who'll put down in writing what you can and can't do with this. The DVLA, VOSA, DfT etc. all end their emails with something along the lines of "this only represents our opinion and it's ultimately down to you to choose". It sucks because the only way to truly find out is to be a test case, which may hurt. It therefore encourages people to exercise extreme caution 'just in case'.
It would appear from your research into this particular case that there's nothing in law to say you can't drive this vehicle on the road. If you tear the road up you can expect to have to pay for repairs in the same way as if a truck is caught ripping up a kerbstone or whatever. The only thing is, in a tank you're more likely to be identified and traced than a truck which can do a runner much more easily. So I'd say it's up to your judgement whether to do it or not. I doubt a copper will be impressed if you've just ripped up the tarmac and your only defence is to say "...but Kevin at DfT said it was ok".