And don't forget how you will insure it on the road. I have held an ADR licence for many years but found it impossible to get cover when I was looking to tow a 1500 litre bowser a couple of years ago. As soon as I mentioned what I wanted to convey every insurance company or broker I contacted refused point blank to provide cover due to the risks. In fact I was told 'I was uninsurable'.
I would be interested to hear of anyone elses experiences who ARE towing fuel bowsers and how they got their insurance cover - assuming that the insurance cover required was to transport Jet A1 (Kerocene) and not just to tow a trailer!