I know your going in a lot of different directions
If it were mine I would..
#1 Clean out the fuel tank, then refill with good fuel.
#2 Take your filter bowl off, fill it with fuel, and reinstall..on my DK, the petcock on the filter housing has off, on ,and prime..Don't know how your Massey is set up, according to the book on my DK you don't have to fill the bowl, just turn it to prime and crank till it starts, I filled the bowl anyway when I did mine, if I was in your shoes I would fill the bowl... mine fired immediately...if this works, run it on prime till it is running smooth then turn to on.
#3 If no luck with number 2, I would get a helper crack a line loose on a injector while cranking, be careful, put safety glasses on, don't have any open flame nearby, it should spray fuel under pressure out around the fitting...If no fuel, check the plug on the fuel shutoff solenoid, mine is on the front of the IP...You should hear this click on and off with the key...If the solenoid is functioning and you have still don't have fuel under pressure at the injectors, I would suspect IP...or lift pump on your tank if equipped that way, and call the dealer at that point.
If you do have good pressure at the injectors, but no luck or smoke, I would at that point look at the injectors. But I think your going to find your problem is before the injectors.
Good luck:thumbsup: