You can find parts (near 100%) for Fordson Dexta tractors online. The Ford/New Holland dealer can get some parts; not all.
Here is the problems. Knowing what to get. Second is what to do with the part. Manuals are written in British generality. Many procedures are written in overview with specific steps left to experience.
With the hydraulics, how to adjust the lift to set the limits is an issue. Book calls for a jig.
Most all the adjustments in the Dexta is in the top cover. It takes less than 1 hr to pull the cover.
Some dealers will do the top cover.
Oscars Fordson page (google it) has the top cover adjustment procedures without a jig.
I bought one of these Dextas, like it so well I bought another running Super Dexta and a parts Super Dexta. I'd rate the Super Dexta near one of the best basic utility tractors ever build.
But they are 50 years old. If you buy a worn out tractor and patch it up, you'll be disappointed with patch work repair. If you go thru it and fix it right, Dextas are near bulletproof. Too bad most buy cheap as possible and just get them running, then they sit seeing only 50-60 hours yearly.
I have noticed a trend. Dexta tractor sell cheap. The nice ones really cleaned up and superbly repair and restored don't sell. It could be the owner is like me and won't part with it. It could be that tractor users don't see the Dexta as a collectors tractor and until the public gets to know Dexta; parts are hard to find for these things, right? They were made in England. (so were the thousand series Fords)