Thanks all.
Gave the battery a good charge this morning, while that was going on I did all the fluids.
Sometime in the past it has had a handy gadget fitted between the fuel filter and the engine which can be used to bleed air out of the fuel line. Even with that it was took a long time to get it going. But when it did fire and keep running it was fine. Spat out drops of carbon black water but settled down and ran as sweet as a hard worked 20 year old diesel engine can be expected to run.
After seeing it upside down up nearly completely submerged I expected it to be a wreck, if not wrecked that it would need a lot of money to put right.
I am so pleased with this little machine, a lot of people here in the UK rave about the cheaper end of the Chinese tractor market, but I would rather have a 20 year old Yanmar to a shiny new Chinese tractor that will probably never get to 20 years old.
Only obvious damage seems to be to the 3 point linkage.