Hi, I bought a 20hp Yanmar F17D two years ago with 750 hours registered. I had a bad experience with a 20hp hunk of Chinese junk, a complete waste of money. However, the Yanmar is brilliant, it works a saw bench and splitter in winter and is used with a flail mower all summer for contract grass cutting. I recently replaced an axle oil seal and service regularly. Manuals were acquired from a US company, parts are easy to source from a lovely chap near Preston. Beware the older British machines, you spend half your life fixing stuff, dont forget how old this gear is!
The comments on prices of Massey's are true, restorers have and will continue to drive the price upwards.
The Yanmar is by far the Rolls Royce of compacts, the engines are the best small diesels in the world, mines about thirty years old and is as tight as a drum. Word of warning though, there is no roll bar or pto guard, the pto is a three speed as well, I am on very flat land and need to get into low spaces but on hilly pasture etc I would want a roll bar.
Road insurance? Easy, call a broker and register it as "plant" at present mine is £150 a year for third party road cover, its the type used for mini diggers etc. That covers trailers and implements.
I have noticed some Japanese machines entering our market that have been refurbished in Vietnam, the Americans hate these citing some dodgy practice. They look good but I cant judge as I dont know anyone who has run one for awhile.
Sorry for the ramble! No, the Japanese build a good product that have an easy life in rice paddies for a few weeks a year, I would not hesitate to go this route again.