Unless I am much mistaken, and not really mentioned on this thread so far...
Operating an ex-RAF Tucano in the UK would be best compared to operating it's predecessor, the JP
CAP632 gives the info you need. Fuel burn will clearly be far less, but if getting it approved via CAP632, and then maintaining it, are anything like as alluded to above, then the JP costs would be cheaper overall
Anyone considering it needs to look primarily at a supporting engineering organisation, and what it would take to get it on a Permit. If those proved satisfactory, it would be a great machine. Until then, JPs are cheap to buy, maintenance is not cheap, but likely far cheaper than a Tincan, and they are faster (and noisier)
NoD